Honest Advice Needed: Am I Being Over Jealous?

Right I'll try and make this as brief as I can: I'm 21 now and in university. Growing up I was always very under confident and had image related troubles (eating disorder and depression etc). Always the one who never had a boyfriend, was never hit on etc. Anyway,basicalllllllyyyyyy.... the guy I am with now we've been on/off for about a year and a half. He's cheated on me countless times. Over the past four months however, he assured me that he never wants to hurt me again- he said i could have hiss passwords for facebook and everything- I know this sounds really unhealthy but hear me out. I know he's always been a cheater since a young age (and he lost his virginity at 13) and I do think he was used to it. Im positive he hasn't cheated on me in the last four months of reforming. I moved in with him and things have been going good. My title is in reference to today being a pure example: He invited me out with his friends for food at a pub. When we were there he talked non stop about how hot the barmaid was and just in general (I feel) disrespect towards me. I feel he takes me for granted - ie I always cook for him and do all the stuff that never occurs to him, even small stuff like changing the bed sheets. I even laugh and joke sometimes about previous stuff hes done to me cause I feel like I have to; but days like today I just feel like WTF. Is it okay for boyfriends to talk like this?! Or am I just being a nag? :/

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