what would you ladies do?

What would you girls do?
My fiancé and I have been together for 2 1/2 years and have an 8 month old son. My fiancé is bi-sexual and his past relationship was an open relationship. Over the course of our relationship I have caught him posting ads for oral fun with other males at least 5 times... I know he has urges to be with other men orally and we've had Mmf threesomes before to take care of urges in the past... I said no more when he brought home an std after cheating on me with a guy at a hotel (he says they only did oral)... fast forward to now, I've given him lots of chances to show me that he wants to remain faithful to me and lots of chances to earn back my trust... I will even let him have oral fun with another guy as long as I'm there... tonight I find on his phone that he posted an ad 4 days ago for a man to come play with him at his work... would you be as done as I am? Right now I feel like I can never trust him again and I don't want my son to grow up thinking that it's okay to do this to someone you supposedly love... what should I do? I'm so torn up inside.