Muggles' Guide to Harry Potter/Major Events/Ron Weasley

Overview.
Ron Weasley remains unattached for the first three years of the series. He becomes infatuated with Fleur Delacour when she arrives for the Triwizard Tournament in "Harry Potter and the Goblet of Fire", but she does not reciprocate his feelings. He eventually falls for the advances of Lavender Brown, with whom he has an intensely physical, but ultimately short-lived, relationship, punctuated by a love-potion induced passion for Romilda Vane. When the relationship with Lavender ends, he moves closer to Hermione, and by the start of the seventh book, they are somewhat more than "sort of together," according to Harry. Their relationship, though it is interrupted by Ron's departure near Christmas, matures over the course of "Harry Potter and the Deathly Hallows" and is further strengthened by his return.
Event Details.
Philosophers' Stone.
Ron is largely unattached through this book. He is impressed at times by Hermione's abilities, and he and Harry do join forces to rescue Hermione from a mountain troll, but there is no apparent romantic attachment.
Chamber of Secrets.
The Monster in the Chamber of Secrets is released periodically and is Petrifying students. When Hermione is Petrified, Ron is apparently more deeply affected by seeing her in the Hospital Wing than Harry is. The only thing that has a greater effect on Ron is when his sister Ginny is taken into the Chamber.
Prisoner of Azkaban.
Ron does not seem to show any particular romantic attachment in this book; in fact, for a long stretch he is estranged from Hermione after Harry's Firebolt is confiscated, and later because Scabbers, his pet rat, has apparently been killed by Crookshanks, Hermione's cat.
Goblet of Fire.
Starting with the arrival of the Beauxbatons students at the end of October, Ron finds himself infatuated with Fleur Delacour, a Beauxbatons student and shortly the Beauxbatons Champion in the Triwizard Tournament. When she comes over to the Gryffindor table to ask if they want their bouillabaisse on their first night at Hogwarts, Ron is almost struck dumb. After she departs, Ron says that she must have some Veela in her ancestry. Hermione is rather nettled by this, and says that nobody else is acting that silly about her, but Harry notices that many other students seem similarly struck by her.
There is also a spot of byplay going on with Viktor Krum, who seems to appear in the library whenever Hermione is there. While this bothers both Ron and Hermione, it is not Viktor himself who is the problem, but the gaggle of girls who seem to follow him about, giggling and hoping for autographs. In fact, at this point, Viktor is still quite a hero to Ron, "the best Seeker in the entire world!"
Matters come to a head at the Yule Ball. Ron asks Fleur to the ball, but Fleur simply ignores him. Shattered, Ron returns to the Gryffindor common room. Harry tells him there that Fleur is one-quarter Veela, and likely had turned on the charm at that moment to snare Roger Davies, but Ron does not seem interested. It suddenly occurs to Ron that he can ask Hermione, but Hermione says that she has already accepted an invitation from someone else. Harry, acting more or less out of desperation, convinces Padma Patil to accompany Ron to the ball.
This is not a success; at the ball, Ron largely ignores Padma, either trying to avoid Fleur or glowering at Hermione as she dances with Viktor Krum. When Hermione comes over to talk to Ron and Harry, Ron accuses her of "consorting with the enemy". Hermione stalks off and is lost in the crowd. Ron and Harry then leave the dance floor to walk in the rose garden.
After the dance, Harry finds Ron and Hermione in a shouting match in the Gryffindor common room. Hermione tells Ron that if he does not like it then, "The next time there's a Ball, ask me before someone else does, and not as a last resort!" Hermione storms off to her dormitory. Ron, stunned, tells Harry that Hermione is quite clearly missing the point.
Even though Ron himself does not admit it, from this point in the story onwards he is quite plainly jealous of Krum, while still hoping to get attention from Fleur. He glowers at Krum, and tries to keep Hermione out of the library; this is often helped by Krum's admirers, who Hermione finds very irritating as they giggle at the sight of Krum.
In the Second Task, the merpeople are holding someone valuable to each of the Champions deep under the lake. When Ron and Harry return to the surface with Gabrielle, Fleur's sister, Fleur is overjoyed; she kisses Harry, and also Ron because he helped. Hermione is somewhat upset by this attention that Ron is getting, but is distracted by something Viktor says to her.
Shortly after this, Rita Skeeter writes a scurrilous article for "Witch Weekly" that suggests Hermione is keeping both Harry and Viktor as lovers. Hermione remarks that she wonders how Rita had known that Viktor had invited her to visit over the summer; Ron becomes very upset at hearing about this invitation.
As the Beauxbatons carriage is getting ready to leave, Fleur comes over to say goodbye to Harry; Ron is once again almost completely tongue-tied in her presence, earning himself a vexed look from Hermione. Ron is still feeling ambivalent about Viktor Krum, but he unbends enough to ask Krum for his autograph before they part.
Order of the Phoenix.
While Ron does not appear to be involved in any particular relationship, he does seem quite annoyed when he finds, in mid-September, and then again near Christmas, Hermione writing long letters to Viktor Krum. Again, Hermione, Harry, and the readers can quite easily see Ron's jealousy, even though Ron appears quite unaware of it himself.
As Ron is leaving breakfast for the Quidditch pitch, on the morning of his first-ever Quidditch match, Hermione kisses him on the cheek. Ron seems bemused by this, rubbing the spot on his cheek as he leaves the Great Hall.
Half-Blood Prince.
Ron is mildly miffed that Hermione, explaining to Harry that he is now once again something of a catch, does not seem to extend the same analysis to him. Ron is, however, a prefect, which does make him more attractive, and Lavender Brown does seem to be laughing excessively at his jokes at one point.
Harry and Ron, taking a short cut after Quidditch practice, run into Ginny snogging with Dean Thomas in the hall. Ron blows up at Dean, and Ginny accuses him of being jealous as he has only ever been kissed by Auntie Muriel. She says that Harry and Cho have been snogging, as have Hermione and Viktor Krum, and accuses Ron of being jealous because he's the only one who doesn't have anyone to snog with. Quite likely in reaction to this accusation, Ron starts responding to the advances of Lavender Brown. This is the start of an intensely physical relationship between Lavender and Ron. Harry at one point mentally compares the pair of them to a vertical wrestling match, and on another occasion wonders which of several hands he can see belongs to whom.
As intense as this relationship is, it is not without problems. At one point, Ron and Lavender seek an empty classroom to snog in. The room they find first is already occupied by Hermione, who had avoided the common room so she wouldn't have to see the two of them at it, and Harry, who wants to talk to her about it. Lavender immediately backs out, but Ron stays to speak with Hermione, and is rewarded by being attacked by a flock of birds Hermione has conjured.
At Christmas, Lavender sends Ron a necklace with gold letters that spells out "My Sweetheart". Ron is revolted, and wonders how she could have ever thought he would like that.
Returning to the school after Christmas, Ron does not seem particularly pleased at the prospect of reuniting with Lavender. He is barely within the Common Room when she has greeted him with a cry of "Won-won!" and dragged him off to a corner. Hermione tries to hide her displeasure behind a "tinkly little laugh," but nobody seems to be fooled by this show.
On his birthday, Ron finds a carton of chocolate cauldrons that had been given to Harry, and that Harry had set aside as being possibly spiked with love potion. Eating two of them, he becomes instantly infatuated with Romilda Vane. Harry takes him off to Professor Slughorn to get the potion reversed, in the process brushing past Lavender. Ron tells Lavender with great excitement that Harry is taking him to meet Romilda. Having cured him of the potion, Slughorn opens a bottle of mead to offer a birthday toast; the mead is poisoned, and Ron, saved by fast action on Harry's part, ends up in the Hospital Wing. Hermione stays by his bedside for most of his first day there. It is noteworthy that, having been silent all day, she finally answers a question, and Ron immediately says her name, and settles into an apparently less troubled sleep.
As Ron's recovery proceeds, Harry and Hermione visit him on several occasions. Lavender corners Harry and asks if he knows why Ron always seems to be sleeping when Lavender visits him. When Harry later asks him about this, Ron admits to feigning sleep so that he won't have to resume his relationship with her. When Ron is released from the hospital wing, Lavender is upset that she had not been told, and that Ron is talking to Hermione.
Hermione, angry at Ron, had been refusing to help him with his homework. When she finally relents, as it seems Ron's spell-checking quill has started making bizarre misspellings, Ron, with a sigh of relief, says he loves her. Hermione says Ron had better not let Lavender hear that. Ron replies that maybe he should, he has been looking for an excuse to break up with Lavender.
Harry, meanwhile, has been thinking about the vial of Felix Felicis tucked away in his trunk. He has been considering using it in the hopes of getting a love interest better matched to Ron, as well as a girlfriend for himself. Finally, having been given a mission to retrieve a memory from Professor Slughorn, Harry uses the Felix Felicis potion to make himself lucky. He, Hermione, and Ron return to the Common Room, but as Harry is under his Invisibility Cloak, Lavender can only see Hermione and Ron, and demands to know what the two of them have been doing up in the boys' dormitory.
This seems to be the precipitating incident that causes Lavender and Ron to break up. Ron, now no longer encumbered, starts paying attention to Hermione, and over the next short while, they quietly become "unofficially" romantically entangled. There is something of a double date atmosphere about an episode with Ron, Hermione, Harry, and Ginny. And at Dumbledore's funeral, Harry notices that Ron and Hermione are sitting side by side, comforting each other.
Deathly Hallows.
On Harry's birthday, Ron privately gives him a book, saying that it is not something he wants his mother to see. Ron says that he'd gotten a copy of the book, entitled "Twelve Fail-Safe Ways to Charm Witches", from Fred and George earlier. Watching Ron later, Harry comes to the conclusion that Ron is definitely using this book in his interactions with Hermione, and with his mother as well.
While Hermione and Ron do not seem much closer than they have been, there are a few tell-tale signs that they are romantically entangled. They dance together at Bill and Fleur's wedding and when they escape to Grimmauld Place, Hermione chooses to sleep beside Ron, and according to Harry, falls asleep holding his hand. After the escape from the Ministry, Hermione is extremely worried about Ron, who has gotten Splinched. However, this is all fairly low-key until shortly before Christmas. Ron is aware of his feelings for Hermione but is, like so many in the early stages of romance, unsure of her feelings for him, uncertainty which we believe is further fueled by the actions of the Horcrux in the locket the Trio are carrying. Finally, fed up with the privations of living rough and suddenly becoming aware that Harry does not have a plan, Ron leaves the group. With Harry's concurrence, Hermione does not shift the campsite until as late in the day as she can manage, and then, knowing that Ron now cannot find them, weeps helplessly while Harry sets the defensive spells and pitches the tent.
When Ron returns some weeks later, Harry gives him the job of destroying the locket Horcrux, with the Sword of Gryffindor which Harry, with Ron's assistance, has retrieved from a frozen pond. In order to try and preserve itself, the Horcrux creates images of Harry and Hermione, and plays scenes of Harry and Hermione bad-mouthing Ron and kissing each other. Despite Harry's fear that Ron would turn on him, Ron instead destroys the Horcrux. When he and Harry then return to the tent, Hermione attacks Ron angrily, and refuses to listen to his story. He relates his story to Harry, however, and Hermione seems to accept it to a certain extent. Over the next while, Harry believes that Ron is quite deliberately taking Hermione's side in any disagreement.
When the Trio are trapped in Malfoy Manor, Bellatrix Lestrange singles out Hermione and tortures her to force her to reveal where she got the Sword of Gryffindor. While Hermione repeats that she had found it in the forest, Ron is a complete emotional wreck, screaming "HERMIONE!" repeatedly as he listens helplessly from the dungeons, hammering the wall in despair and helplessness. It is perhaps worth mention that, as they escape, Ron carries Hermione to Shell Cottage.
After arriving at Hogwarts, Ron and Hermione vanish. We find later that Ron, having memorized the sound that Harry made to open the locket Horcrux, has opened the Chamber of Secrets, and he and Hermione have retrieved several Basilisk fangs. Hermione has used one of them to destroy the cup Horcrux. Ron now suggests that they should go to the kitchens and warn the House-elves that a war is coming so that they can escape to safety. Dropping her Basilisk fangs on the floor, Hermione sweeps Ron into a fierce embrace and the two share their first kiss. 
Ron and Hermione fight side by side through the ensuing battles, and both survive.
In the Epilogue, we see that Ron and Hermione are happily married with two children, Rose and Hugo.
Notable Consequences.
Ron's infatuation with Lavender causes several months of estrangement between Ron and Hermione. Ron does not seem to completely understand why this is happening. Harry does understand it, and with his insight into how rocky the relationship between Ron and Lavender is, occasionally tries to smooth things over between Ron and Hermione. One notable attempt ends with Hermione sending a flock of conjured birds to attack Ron.
When Ron departs and cannot find his way back to Hermione, the experience seems to change him. When he does finally return, he seems more secure in himself, more self-assured, and much more aware of his own feelings. We see him making a conscious if clumsy effort to placate Hermione. During his absence, he seems to have recognized, first that he truly misses Hermione when they are apart, though he may not yet be willing to accept that it is actually love that he feels for her; and second, that he has rather seriously wronged Hermione.
The eventual marriage of Ron and Hermione is, of course, a notable consequence as well.
Analysis.
In pretty much every way, Ron's romantic relationships develop along a very realistic path. He is clearly somewhat immature relative to Harry and Hermione, and this lack of maturity does frustrate both Hermione and Harry in the first few books of the series. It is only after Ron is forced to live apart from Hermione, with Hermione quite likely in danger, that Ron gains the maturity to be able to deal properly with the relationship. Until that point, it seems that Ron's romantic life had been purely driven by others, despite the underlying and unacknowledged affection for Hermione. In particular, his infatuation with Fleur Delacour is driven by her Veela ancestry, and the affair with Lavender, started by Lavender herself, is triggered by the quarrel with Ginny, and maintained by Lavender almost exclusively. It is perhaps apparent, particularly in her choice of Christmas present, that Lavender has created an image of Ron and is infatuated with that image, rather than with the actual person; Lavender has taken no time to learn what Ron likes and dislikes. It is only when that relationship is terminated that Ron finally starts a relationship on a more equal footing, though again it is not Ron, but Hermione who is doing most of the driving of the relationship at that point.
Despite Ron's becoming more mature in the latter half of "Harry Potter and the Deathly Hallows", one does question exactly how mature Ron is when we see in the Epilogue that he had to Confund a Muggle driving examiner in order to get his license. This use of magic to avoid consequences of one's actions does indicate a certain lack of maturity even almost twenty years after the end of the story. However, the jovial mood he demonstrates as he jokes around in the epilogue with the others, including Hermione, who is by now his wife and mother to their two children, shows that they are content with their relationship.
Greater Picture.
Key to the enjoyment of any piece of fiction is belief in its characters; without believable characters, one simply does not care about the story. The author had plotted out this story to cover a span of nearly seven years, in the lives of characters starting the series at age 11. Knowing that her characters were going to go through adolescence, she also chose to write their relationships as an integral part of the story, rather than simply ignoring them in favour of the main quest, as is common in heroic fiction. The depiction of Ron's romantic life, while possibly not totally realistic (as the end of the relationship with Lavender is simply too convenient to be fully believed), is key to making Ron a character that we can believe in, and one we can like, rather than a cardboard cutout that we could, perhaps, admire. This same attention to life outside the main quest is present in many characters, even those not key to our story; in particular, the romance between the two minor characters Lupin and Tonks is completely extraneous to the main story but is critical in making these two into characters that the reader can empathize with. The author's treatment of Ron's relationships is thus part of a larger pattern, where we are allowed to see not just how the plot unfolds, but how the people driving the plot, or driven by it, mature and change through the 7-year story arc.