My now ex and I had been dating for about four months and a month or so ago he told me that he has a fat/feeding fetish. I tried to be supportive but told him I am not gaining weight for his sexual pleasure and so on. I don't care if he watches porn or what he does but messaging girls on his fetish subreddit and commenting suggestive and flirty messages on their nsfw pictures is cheating to me. I told him about my ex of a while ago that did that too and how it messed me up and how I look at social media. 

I worked up the courage to just break up with him and now he is begging for me to have him back but after a lot of other things this was the last straw. Am i right to feel cheated on when early in the relationship we created boundaries about this. When i even asked him about it before I even caught him he looked me dead and the eyes and promised that he wasn't doing it.

I'm tired and sad