Problem With Boyfriend At The Dance

At the dance on Friday everything started out fine, then my friend Kendly came and we hanging out and he got mad, after that he asked me if it was ok if he pretended to go out with his exgirlfriend to see what she would if he cheated on her like she did him. I said ok then i knew i made a mistake then i tried to figure out why i said ok to that. I was in the bathroom talking to Kendly when he had my neighbor come in and tell me that it was over i was driving him crazy. So I her tell him he wasnt worth it. Then on Sunday he called and said sorry for making me cry and asked me back out; I told him i dont I`ll have to think about it. So I need advice take him back or say no.