Though you might have been together for over a year, or even five, that doesn't mean that he's ready to marry you. Some men want to get married eventually, but only when they are ready. The concept of "ready" is complicated and often involves a feeling that he has "played the field," had adventure, had independent fun, is financially stable, is mature and now ready to settle down. All of these are valid reasons and you shouldn't ignore him and force him to do something that he's just not ready to do.  See if he's committed to you in any way other than calling you his girlfriend. This could mean moving in with you, sharing a pet with you, moving to a new location with you, or even putting himself in the same exact social circle as you. See if he's had other relationships. If he's had significant dating experience before, then you shouldn't be jealous, but fortunate that he's had some experience with women and is more likely to feel less interest in "playing the field" and seeing what else is out there. Every relationship is different, and many couples who got engaged after being together for just a year or two can have marriages that are just as successful as those of couples who waited five or ten years to get married. If it's not the right time in your man's life, then it doesn't matter how long you've been together.  If he's still trying to figure out his career, if all of his buddies are still single and not even really dating, or if he still has a lot of personal issues to sort out, then it may not be the best for him to marry you. If he's not feeling stable personally, financially, or even physically, then his mind may be on other things. Still, keep in mind that there's no perfect time to get married. If it hasn't felt like "the right time" for years, then there may be bigger problems. If you want to get your long term boyfriend to propose, then you should make sure that he can't imagine his life without you. Sure, you've been together for three years, but does that mean he wants to be with you for...

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Write a summary of the previous text in Vietnamese:
Chắc chắn anh ấy đã sẵn sàng cam kết gắn bó. Chắc chắc đây là thời điểm thích hợp trong cuộc đời anh ấy. Chắc chắn chàng không thể nhìn thấy một tương lai không có bạn trong đó. Cảm nhận quan điểm của chàng về hôn nhân.