Hey girls. I have a question but hers some information before that's ralivent to it.

My boyfriend and I are 17. Been together practically 2 years. Off and on a bit. But we come back to each other no matter what. I wanted to have an open relationship to see why we were never working out the way we want to, so this past summer I asked him if he was okay with it... he said he was. Over the summer I started seeing this other guy and it was so nice there was no fighting. I liked him a lot except he left for college this fall and I knew I'd never see him again. This weekend he plans to come up to spend time with me( him knowing I have a boyfriend, just as friends) my boyfriend then brought up the fact that I had sex with him and another guy over the summer, after the fact I have apologized many times and him saying he was okay with it many times over the summer Yet he still brings it up as a comeback for anything he did that I don't like... ie go to a friends ( to drink or get high) when we had plans to go out for dinner and didn't tell me till I was at our appointment almost ready. So ladies my question is, Is what he is doing okay after saying he was fine with an open relationship? and what do I do about it?