Sure, you can say life is repetitive .
There's nothing wrong with that.
It does sound like a general statement, though, and not a description of specific things we do over and over again.
So how do we describe things we do regularly, over and over again?
You can talk about your daily routine .
That means something you do every day, though you can also use it to describe things you do only on weekdays, in which case you might say weekday daily routine or daily routine on weekdays .
(Some people skip over this detail and just say daily routine .)
You can also talk about your habits .
Do you make it a habit to clean for ten minutes every day after you get home from work?
Then you can use that word.
If you don't exactly form the habits on purpose, then you might say you're falling into a routine .
And any activity you engage in on a regular basis can be called habitual .
Of course, habits can refer to both good habits , like brushing your teeth regularly, and bad habits , like smoking.
If you're getting bored of doing the same things every day, you might describe it as tedious , or as a noun, tedium , as in the tedium of daily life .
You might say that things are getting old , or that you're getting tired of doing the same things day in and day out.
If you really want to change, you might say that it seems like your life is standing still , but you want to move forward .
(This, of course, is a metaphor.)
Another good alternative, suggested by Mistu4u, is monotonous .
This word usually has a negative connotation, much like boring or repetitive .
You can say that your life has become monotonous, or if you like the "life is..." formulation you started with, it certainly works there, too:
Life is monotonous.
Again, that would sound like a general statement about life, though you can apply the word to individual activities:
Work has been so monotonous lately.
Of course, there are a lot of ways to talk about things like these, so I suggest you wait around to see if anyone else posts an answer :-)
They might have a term or a phrase that you like better.
ell.stackexchange.com/users/230/snailplane
In addition to "routine" and "habit" you might say that you are "stuck in a rut".
(That is a reference to a wagon whose wheels only go straight because of the rut in the road.
Turning the wagon is difficult as is changing one's routine.)
ell.stackexchange.com/users/1811/TecBrat
High-level English users sometimes borrow the French word quotidien, an adjective meaning "everyday".
You can also, of course, use the adjective "everyday", but remember that it's not the same as saying "every day" (indefinite pronoun + noun meaning something like "each day").
ell.stackexchange.com/users/9933/Deirdre
In reference to the original question, "Is there any word to describe things we do regularly over and over again?", if you were to ask me how things are going, I might answer, "Oh you know, same old, same old."
In this case, "same old, same old" refers to things that are done regularly over and over again -- all mundane, monotonous, and humdrum things indicating that someone is stuck in a rut.
ell.stackexchange.com/users/56720/Pat Hanham
The second example in your question: Another example would be when two lovers spend too much time together, and fall into a pattern of always doing the same things over and over; nothing appears to change.
reminds me of another word: humdrum ( humdrum = boring because nothing new or interesting ever happens).
Here is an example from The Everything Guide to Writing Your First Novel: All the tools you need to write and sell your first novel by Hallie Ephron: Bridges of Madison County is a literary romance in which Iowa housewife Francesca Johnson, stuck in her routines and a humdrum marriage, meets a handsome photographer who turns out to be her soul mate, and must choose between true love and her family's needs.
ell.stackexchange.com/users/3281/Damkerng T.
One way of describing a welcome routine is tradition .
Although we often think of this word as referring to old customs, it can also refer to more small and routine things.
Macmillan lists one definition of the word as: tradition ( n. ) an activity that happens regularly and has become the usual thing
For example, one author wrote: He pushed the hall door open and, as was his tradition , let it slam behind him .
(Jinna Dodds, Light Song )
ell.stackexchange.com/users/5630/Krystal Young
I think the word you’re looking for is “mundane”.
Mundane adjective 1. common; ordinary; banal; unimaginative.
Source: dictionary.com definition of “mundane”
ell.stackexchange.com/users/15333/Redink
One of the words that comes to my mind is- monotonous : not changing and therefore boring
You can use it in such conditions.
Say... a monotonous job or life...
ell.stackexchange.com/users/3187/Maulik V
I found the perfect idiom, which I happened to read just now in the early edition of Anne Frank's diary (still in print and being sold on Amazon or Adlibris) transl.
by Mooyaart... "the common round".
It is 2-3 pages in, where Anne complains that she rarely departs from the usual routines of talk with friends, but can now truly confide in someone -- her diary!
Note: I could not find this phrase in any online dictionary, but it seems the perfect thing.
If Mooyaart coined it, then she has just enriched the English language.
ell.stackexchange.com/users/49069/Nicholas L
CONSISTENTadhering to the same routine, as in "makes delicious coffee ever time.:or "always comes to work with a smile on her face."
ell.stackexchange.com/users/89535/SpindoctorUSA
Ritual (of an action) arising from convention or habit. "the players gathered for the ritual pregame huddle" (Lexico)
I think this word has more of the depth and connotation the asker is looking for rather than the simplistic words like repetition and habit.
ell.stackexchange.com/users/107446/Carrie 
For example, when in our daily life we go to school, do homework, go to the gym and then go to sleep, but all these things we do for a whole week. Repetitive things.  Another example would be when two lovers spend too much time together, and fall into a pattern of always doing the same things over and over; nothing appears to change.  Is there a word to describe this?   Life is repetitive.   Is that correct?
Is there any word to describe things we do regularly over and over again?
ell.stackexchange.com
<word-usage><word-request>
ell.stackexchange.com/questions/10874
ell.stackexchange.com/users/2740/Daniel Fuentes
Suggestions include: repetitive, monotonous,  routine, habit, stuck in a rut, tradition, same-old-same-old, ritual, and mundane. Monotonous, repetitive and mundane are options with a negative meaning. More positive expressions are tradition, ritual and same old.
Monotonous, repetitive and mundane are options with a negative meaning. More positive expressions are tradition, ritual and same old.