My ex likes me, what do I do?

Move on. It sounds like he wants you to be his safety net so if a girl dumps him he can go back to you so he won't be alone. You deserve better than that. Keep in mind that you choose who you go out with, and if you don't want him then do not go back to him. Remember why you broke up in the first place then ask yourself if that would still be a problem. Try to think of anything that would ruin the relationship this time around so you can save yourself a little heartache.