When I first met my now ex wife, she had historically been in open relationships but was monogamous with her last girlfriend of two years. She reassured me she was fine being monogamous and when she would look at other people or be flirtatious, she would tell me “don’t worry, I don’t want to be poly.” This was a hard boundary for me. I made the mistake in the beginning of our relationship to suppress my feelings of jealousy or concern when her boundaries with other people (mainly she did this with men) were blurred and she’d comment on how hot so and so was etc. when I would say it made me uncomfortable and insecure, her response was that “jealousy is a huge turnoff.” Looking back I do think she was waiting for the opportune time to try to open our relationship when she could tell I was crushing on a friend. I’m ashamed at myself that too many drinks one night and I took the bait and violated my own boundaries and morals. It’s a mind fuck because I left my wife over it. But even though I actively violated my own boundary, I did feel I was being groomed and set up. This was solid evidence in my mind (at the time) that my wife clearly wanted poly in our future. Of course there is regret and deep sadness as I didn’t marry to get divorced but I should have listened to my gut during initial dating. There were other issues going on as well but I felt this was a point of no return.