When does a guy know?

How early in a relationship does a guy know whether he can get serious with you?

My mother wants me to break up with my current boyfriend because he did not propose to me at his graduation. But we'd only been together for 4 months. But she says that guys propose at graduation to make sure they stay together, no matter how short a time. She says that he knows already and that since he didn't propose he's just dragging me along for sex.

Do guys really know that early in a relationship? I mean, I never withheld sex from him and its been really good, but he can get other girls if he wanted. If he had asked me at 4 months, I would have said no because that's too early, but I do really like him and want to see if it does get serious.

Is he just keeping me around for sex? Does he know already that he doesn't want to get serious with me?
When does a guy know?
Add Opinion