Boyfriend issues- help me!!?

I think you are right, he should clean things up, but you should approach him differently about it. You are saying you want him to do this ONE thing only for his apartment. That's not much. Tell him without sounding like a mum, but rather encourage him. Make sure he knows that if he does clean up after his friends have come over, you will really appreciate that. Focus on the appreciation he would get, rather than the complaint about it not being done...I'm a guy. The last thing I want is to hear my GF nag about some stupid trash lying around and how I should clean it all up. But if I would be challenged, and would be made clear that this would make my GF feel so tremendously much better, I'd be mature enough to do it for her... you feel me? This is just my intuition talking. Hope it's of some use!