Having been in a controlling relationship I can tell you that you need to stop his behaviour now or else it will only get worse.
He's acting insecure and probably feeling a tad bitter at times that you have more friends with him etc. This is understandable, but if he really loves you, he shouldn't want to hold this against you.
You need to talk it out with him the next time you see him, reassure him that there is more to uni than shagging around and that just because you go out often and have lots of friends, it doesn't mean that you are out cheating on him etc.
He's only going to drive a wedge between the two of you if his bitterness carries on escalating, he probably needs to know this so that it might force him to address his insecurities.
Good luck!