My ex and I share our 19 month old son together so we see each other twice a week to drop off our son. He has a gf who he has been with for over a year now I believe and I have remained single since the split.)
At the beginning of their relationship about 4 months after our split he would constantly flirt with me and try things on even though he had a girlfriend but I would just ignore his advances, and then he completely stopped so I assumed he was taking his relationship seriously. We are friendly (always banter and completely cordial, no boundaries crossed on his end since).
Recently he came over to drop off our son and was flirting with me excessively and told me not to worry about his girlfriend, as she's waiting for marriage to have sex which he doesn't want to do. Then he kissed me and started grabbing me and trying to have sex with me (then I pushed him off.)
He was then saying how he wants to propose me and him having sex with no feelings involved until him and her marry just for his sexual urges. Then after I refused and said no he begged me not to tell anyone be it friends or family and that he regrets what he did and has no idea what came over him saying he loves his gf and wants to marry her and he didn't mean anything he said or the kiss.
He left to go on a date with her (scum), and now wants me to meet her and for her to meet our son and is pushing for an engagement. I absolutely do not want to meet her or for her to meet our son as they most definitely won't last due to obvious reasons, but I also don't want to get involved in their relationship or tell her what he did.
I feel so guilty even though he kissed me and was the one grabbing my body and flirting with me and I don't want her to meet our son because I really don't think he loves her, although he said he does and that it was just because he was horny and having to go without sex why he made advances to me. Am I wrong in not saying anything to her or asking that she not meet me or my son? We both agreed that we wouldn't bring people around our son unless it was 100% serious. And I'm so upset that he is trying to use me for his sexual urges because he is unhappy with the dynamic of his relationship with his gf. What do I do?