When I Cheated on My Wife with an Ex-Boyfriend She Knew About

I've been married to Sarah for seven years now. We have a comfortable life and two wonderful kids, but lately things just haven't felt right between us. A few months ago, we had a conversation about past mistakes - specifically my brief affair with Mike when I was in college. Back then, Mike and I both agreed that it wasn't real, and after a year of dating and some wild nights, we went separate ways. Sarah knew all about this old fling, but she's been so understanding about everything from our past. She even helped me move on by telling me to 'leave the past behind.' So here I am, still married, with kids who have never had a stepdad or a real dad figure in their lives beyond my relationship with Sarah. But you know what? In April of this year, Mike contacted me out of the blue. We caught up over coffee and dinner a couple of times, but it was more like friends than anything else - until that night when we met at a bar after our drinks together. He had been single for quite some time too. I felt something in those moments that I hadn't felt with Sarah in years... or ever really as her wife. We ended up back at my place, and it was just like old times. It's not like we planned anything, but the connection was undeniable. Sarah hasn't found out yet, and honestly, if she does, I don't know what to do. But here’s where things get tricky - is cheating ever justified if you’re both aware of your exes? Should that past have any place in a current marriage? Am I the asshole for keeping this from Sarah even after our talk about my past? And would it be wrong to feel like it's okay since we were both open about history and no one got hurt back then?