The guy Im talking to (lets just call him Bob) is either talking to other girls or dating someone else. He has called me his girlfriend and brought up marriage (not too seriously though, we're still in college).

I personally don't have a twitter but when I look at his page, there are always posts between him and one girl in specific who calls him her boyfriend and makes it seem as though they are together and he doesn't deny or put a stop to any of it.

A few weeks ago at a party, one of his friends was drunk and came up to me and (probably unintentionally) apologized for "the way he [Bob] did you" before this I had seen some of the posts between them but I didn't want to draw conclusions if they were just good friends.

Obviously they are more than friends. But my question is how should I approach him. I do have strong feelings for him as a person, and if only he would be more committed to one person, then there'd be no problem.

I also wonder if I should approach the other girl, just as a heads up. But I know not all girls would want to hear that from someone else talking to their boyfriend.