I'm glad you have a friend you can talk to. That matters so much! I didn't confide in friends until they started to notice something was wrong. It was a relief, but it also created some emotional distance, just the tiniest amount, and that made my ex even more possessive.
He cheated on his ex but always told me it was because she cheated on him and he couldn't forgive her. Man - have I just been blind?
I heard this from my ex too, the exact same thing
It was what drew me in, when I think about it. I thought he had been so poorly treated, and hurt. How could this woman treat him so badly and hurt him like that? I knew I would never do that to him. But then shortly after we got married he cranked up all these infidelity accusations against
me, as though I was his ex-wife. So confusing.
I don't think it's blindness. I read somewhere on this board about how we internalize the accusations and become steeped in the defense, focused on proving our innocence. We stop examining our own feelings about what is happening. Something about what happened to you recently jostled this pattern, and you began to seek information to confirm what you suspected.
Sometimes I think of my inner emotional life as a diverse member organization, with some members dominating more than others, all sitting at a big table making decisions, floating some information to the group as they deem necessary.

My own board of advisors. Maybe there is a changing of the guard for you, and other voices are having a say at what is best for you.