Ended things with my AP - Regret and Pain

I ended an almost 3 year affair, about half a year ago. My AP and I were friends at first, having met about 5 years ago. We worked together and worked a high stress job, putting in a lot of hours together. I was married and she was seeing someone. I always was attracted to her but because I was married and she was with her partner, I didn't have any emotional/physical urges, I was just happy to be friends. She also shared the same viewpoints as me on life, politics, and religion which made her extra special as a friend.

Flash-forward a year and a half, her partner and her break things off. Another half year later, we're out for drinks with coworkers and I discover that she's had feelings for me since the beginning.

It was a shock to me, but we started seeing each other. My wife was not living at home at the time due to work, which made it easy for me to live with my AP. We learned that we were nearly perfect for each other. We could do just about anything together. We lived at her house, we got ready for work and came home together, we traveled together, everything together was honestly perfect. Those moments were some of the happiest I had ever been.

After about 3 years, many job changes, relocations, etc. Juggling this affair with my home life became nearly unbearable. My wife and I were fighting all the time (due to recent stresses from raising a child, living in her parent's home, and changing jobs). On the other hand, my AP was pushing me to leave my wife and I was terrified of losing contact with my child. At the same time, my AP was becoming an emotional wreck waiting for me to make a decision, and the guilt of putting her through so much pain helped me end the affair.

I decided to end the affair, for her sake and my daughter's sake, so that I could repair my marriage and focus on raising my child. It was one of the hardest things I had to do because I was absolutely in love with my AP. I wish she had come into my life before my marriage.

Flash to present time, I had cut off all communication with her, as a way for both of us to heal. I then saw that she was dating someone new, relatively recent. At first, I was okay, I was happy that she had found someone. But then all the emotions flooded in, and my unhappiness with my marriage creeped in, and I couldn't bear it any longer. I reached out to her and we started talking again.

She's still in love with me but she also says that she's happy now. She doesn't know where this relationship is going to go but for the time being, she says this is the best thing for her. Seeing me while I was married was extremely painful for her, and she was willing to make that sacrifice only because for 3 years I gave her hope of leaving. When I ended things, that hope died for her and she needed to move on. Maybe if I could make a change, then there could be a path-forward.

Present day, I told my wife how unhappy I am and how I don't see how she could be okay with all of the fighting. She essentially stated the same, and neither of us really want to work things out anymore, and just move on.

Im posting this to vent but also to ask, is it a mistake to attempt a relationship with my AP once-more or should I repair my marriage? I want to be there for my daughter but I also don't want to raise her in a miserable household either. There was a time where my AP and I were absolutely infatuated with each other and every waking moment we spent together was perfect for the both of us. But I think my AP is scared of being hurt once-more and I don't know how to fix that. It's my fault for cutting off communication. At one point, we were both unhappy looking for happiness with each other. Now, I'm the unhappy one, and she's the happy one with an uncertain future with a new partner where things seem to be moving along well.