My ex is confusing

A couple months ago I started speaking to my ex again (after three years). I was maybe hoping to understand a different side to him. The relationship ended with him leaving suddenly with no reason. He didn't really give me a reason for breaking up with me and basically just said "everything was my fault". He apologized for breaking up with me like that. Recently, he's been trying to see me (or so I assume). He asked me to hang out twice, and both those times he canceled. The first reason was a real emergency but the most recent one I don't know. I guess I feel stupid for allowing him back into my life and him continuously canceling plans, brings up old feelings of not being important to him. Should I just stay away from him?