AITAH for falling in love with my ex-wife’s best friend

A bit of an overview:
My ex-wife and I were together for 15 years, married for 8 years. We have 3 kids together who are now 11, 10, and 7 years old. We divorced in 2021.

My Story:
I worked full-time, was the primary care taker of our kids (woke them up, got them ready for daycare, brought them there, picked them up, cooked dinner, got them ready and put them to bed, etc. My ex worked FT too but had a difficult time balancing much during the week. In about 2017 she became very verbally abusive with me - everything I did was wrong, the way i took care of the kids wasnt right, she always shamed me for everything I did, etc. She became very dependent on her parents for some reason and put their needs/expectations above mine. She wasn’t excelling at work while my career was taking off and she began taking it out on me. I suggested over and over again that we should do therapy together because it wasn’t working for me but she denied it and said there’s nothing wrong with her but if I wanted to do therapy I can.

In 2019 we went on a vacation with our closest friends, I’ll call them Samantha and Jerry, and one night we all got pretty drunk. My wife and Jerry decided they wanted to play truth or dare and slowly started daring they Samantha and I do physical stuff together (hug, kiss, touch her breasts, her grab my penis, her suck me off, etc.). We basically wound up swapping spouses that night… for the few weeks after that my ex-wife and Jerry were continuing to push that we did things together, which we did. Then my wife told me she wanted to stop because she was insecure about it, which we did stop. She then became even more verbally abusive with me, blaming me for doing everything because I didn’t say “no”, telling me that she’s insecure because I don’t lift her up enough, etc. She stopped talking to Samantha because she started blaming it on her too. Note that I was the one supporting her with everything she had going on, even when she was having some challenges with work and suggested changing careers I told her I was supportive of her quitting, going back to school, and finding a new career.

One day early 2020 while traveling for work I had a random mental breakdown. I couldn’t deal with the stress and her putting me down anymore and was starting to hate myself because of the way she was making me feel. I immediately came home and told her I needed time away from her because I couldn’t take it anymore. I went and moved in with my sister for a few weeks and during that time I realized how good I felt for not being picked on or put down all the time so I decided I wanted a divorce. I found a house and moved into it in May 2020 (great timing, I know) and we started custody of 50/50 while working on the divorce papers. My friends group ostracized me because I must have been some horrible human for asking for a divorce and suggested I must be having an affair or something, and suddenly I had zero friends. During this time I heard that Samantha and Jerry separated and completely divorced too, but I didn’t know first hand because I didn’t keep in touch of either of them anymore.

My ex and I rotated holidays and she had them on New Year 2020. Everywhere in my area was closed because of COVID so I decided to stay home alone, get drunk, and watch the ball drop. At about 11pm I decided to make the dumb or smart (not sure) decision to text Samantha to ask how she was. Throughout our texts she told me she was with a new friend group at a house just a couple miles up the road from my house, so I went and met them there. Her and I already hooked up because of the situation above so when the ball dropped I kissed her, which ultimately led to her coming back to my place and us sleeping together. I kind of joined her new friend group and her and I hooked up every couple weeks, then every week, and then every couple days - you get the idea.

Almost 2 years later, in late 2022, we decided to give the exclusive dating thing a shot… I didn’t expect to have feelings for her and really started as a way to feel something again but it grew. We hadn’t hung out with our original friends for years, only saw our ex’s at sports activities, and didn’t mingle with our ex’s families anymore so figured they basically removed us from our life so how is it a terrible thing to start building a life together? I’ve never been happier!

Last night at a grocery store I ran into one of my old best friends who never even reached out to me once during the separation or divorce. I said hey to him and he said “hey, I really have nothing to say to you. Samantha and you getting together makes you both assholes.” I responded with “it would have been nice to have a friend when I needed one the most, so I’m glad I had Samantha to lean on when you were MIA” and we parted ways.

I get that it would have been an asshole thing to do if we were still in the same friends group, or if we were still married, or if any of us were still friends with the other’s ex spouse - but none of that was true anymore. AITA!?