@Kaelyn,
Think hard about what you want from him: friends? friends w/benefits? is he the one you want to spend the rest of your life with? Or do you just enjoy spending time with him? You don't sound like you're quite "spend the rest of your life with him" stage of your life, in which case, ask yourself if all this angst is worth your time. If he says he wants to be single, then that means he wants to still be with other people - either as friends or more than friends. If you're okay with that, then that's that...you let him live the 'single life' with you by his side.
If you're not okay with that, and you still see him as the one you want to spend the rest of your life with, then you have a problem, because he's not ready to commit to you. And you can't change that - he has to decide for himself. If you force it, he will resent you for 'taming' him. If you smother him to try to make him want you more, he will feel stifled and miserable. In this case, I would recommend letting him go to be his single-self. If he comes back to you on his own, then he really does love you, and has decided that he wants to spend the rest of his life with you....you wouldn't have forced him to make that decision, so he won't resent you. If he doesn't come back, then it was never meant to be in the first place.
If you're just friends, or friends with benefits, then get that clear in your head. If you don't see this person as the person you want to have a long-term commitment to, then he's just a friend...let him be single, and you can be as well. But you really have to make sure you are okay with him being with someone else if you take this route. Also, if you do this, be open with him and say that from a safety perspective, you need to know if he's sleeping with anyone else...you don't care if he does, you just need to know to protect yourself.
Good luck with the situation, it's tough. But from personal experience (very similar circumstance), let him go. Live your life, enjoy the happy memories, and move on. If he comes back to you, he's yours forever. If he doesn't, then it was good you let him go. It's cliche, but true.
PS - when I let my 'him' go, I found out that he had already lived the 'single' life for about 3 months. And I promptly punctured two of his car's tires before letting him go.