Hi Op, I've name changed for this.
I've been in your shoes.
I thought my relationship was dead. We had a young daughter, our sex life was down the shitter and I was utterly miserable. I felt like it was give give give from me and nothing in return. I felt unappreciated and told myself our relationship was dead, but I was staying for our daughter, and because I felt sorry for him.
A colleague paid me attention, it became an addictive thing. It felt new, and exciting! Like the beginnings of a new relationship, I felt like I'd found "the one".
I started an emotional affair. I went so far as to ask my partner to leave, I didn't tell him about the other guy. He left. Over the next couple of weeks, seeing my family disintegrate, I started to feel a bit strange. The exciting new thing didn't feel quite as exciting anymore once the "forbidden" factor had gone. I started to wonder why I had suddenly decided to end my relationship to be with this guy, when I'd been telling myself for so long that I was unhappy. What was it? Did I NEED to be with someone to be happy?
Then I realised that I needed to breathe. Be alone and to think about exactly just what the fuck I was doing. Because whatever it was, in the cold light of day it felt wrong.
I asked the other guy for some space. He gave it to me.
I started to realise that cracks in my relationship seemed a lot worse once the other guy entered my life, and I became distant and cold to my partner. Which made the relationship fail even more.
I also started to realise that I missed my partner. I loved him. He was comfortable, we were good once and my family felt broken.
I didn't love this other guy. It was limerence. I loved the idea of an exciting new relationship, new feelings. Feeling special.
I made the decision to come clean to my partner about what had happened. The only way we could start again was a new slate.
A lot of talking was done. And crying. We decided to give things another go. I told other guy it wasn't going to happen.
This was 7 years ago, and our relationship is once again where it was before the rot set in. The rot being, the other guy and his attention. We are happy, family life is good. I've accepted that it's never going to be constant flutters and clothes ripping off. That intense passion does quieten, but that's ok. I've accepted that, and I'm content.
I'm lucky, I very nearly made the biggest fuck up of my life.
Be sure this is what you want.