you intentionally picked a married man, and helped him cheat on his wife.
This is not true. They had been separated two years when I met him and she had been dating her bf for a year or so.
It was very obvious he was still tangled up with his ex wife. Why did you insert yourself in such a situation and keep clinging on despite deep down knowing it’s not right?
One of the issues was that it was a drip feed. He minimized the extent of their relationship for a long time. I only found out things as time went on, for example the extent of their daily texting and the secret meetings, and the fact that I wasn't invited to join them. When it came to a head he agreed to divorce and step back from her. When it comes to a head, he does eventually see things from my point of view, and chooses to prioritise me, it just isn't his first instinct.
Another key reason why I stayed, rather than cutting him off, is because I felt unsure I had a right to, and thought that the issue was my insecurity (that I could work on) in line with what PPs here are saying. I tried to work on my insecurity about it and failed.
Some posters here have told me to access therapy. I did actually find a counselor last time, when things were coming to a head. And she told me "there are three people in this relationship. You, your bf, and his wife." And counselled me to that effect. That did help me have the conversation with my bf that time, and he agreed to cut contact down, stop lying to me, and divorce.
Now you've made him cut her out completely, I'm really not sure what effect that will have on your relationship. And I suspect it'll only be five minutes before you find something/someone else that will trigger your jealousy.
I don't think this is the case. For the past year, I thought they weren't in contact and I've felt incredibly more secure in the relationship. I haven't had other jealousy issues in that time. I haven't made him cut her out, he offered this after seeing how upset I was, and it being obvious that something has to give.
I’d be of the opinion that our friendship as dear as it is to me, shouldn’t trump his main relationship and I wouldn’t be happy if I was causing stress in his marriage.
The fact that both of them are so willing to continue with this when it risks his current relationship says a lot
This is how I feel. I have a close male friend. When he got a long term partner and kids I did see less of him, and speak to him far less. I thought that was completely understandable. I wasn't arranging private dinner dates with him and ramping up the contact, which is what seemed to be happening between my DP and his exw when I came on the scene. My friendship with him was never secret, never minimised. When I meet with friends, I often bring my DP along. DP wanted solo meetups with his exw that excluded me. I think it's difficult for people to see my situation, when they have a similar situation (but less intense and obviously more normal).
It's more probable that he has an aversion to intimacy and is choosing to spend time with her because she represents a safe and non-threatening option.
This could well be true.
You can't control other people's choices, only your own. Right now your choices are: stay and accept that he has this intense friendship with another woman, or decide that that isn't for you and end the relationship.
These aren't the only choices. He could make changes.