What do you do if an X friend returns???

So what do you do when a person that used to be your friend wants to be your friend again?? I guess I should elaborate. This person that I was really good friend started dating someone and started ignoring me and my other friend. I was a little annoyed at first because he did not want to date this guy to begin with and only because my friend and I talked to him did he decide to give the guy a chance. That's kind of beside the point. So I tried keeping in touch and being a good friend and hang out and stuff, but he always had something to do or his boyfriends friends to hang out with. Eventually I just gave up. I believed that if our friendship was that important to him then he should have tried to make more of an effort. Now after a couple of years we have started seeing each other at a friends parties, we are cordial but I don't go out of my way to make myself available to him. But he kind of hints that he wants to at least maybe hang out some time. I don't know how I feel about this. Well I do know how I feel about it, I don't feel like I want to. I think that maybe there is still a bit of anger that he would have let our friendship fade when we were supposed to be best friends. I know, I know what your thinking. He was dating someone he needed his space. But that was sooooo not the case. If you want details you will have to ask in person because I don't feel like putting them all on here. I just don't think I want to put any more effort than I already had into that friendship. Sometimes its just better to let it be what it was. One of my good friends told me " It is what it is until its not!" So I don't think I can move on from what happened to our friendship and I am happy with the friends I have now. It may be mean but I cant change how I feel about it. At least not right now.