I have never had a physical affair but have definitely crossed serious lines emotionally, I had a few serious relationships before my husband, two in which I was in love. Both ended years ago for valid reasons. A few years ago, I began obsessing over one of them, thinking I'd made a mistake, I should of ended up with them, we reconnected online and they said all the same things. It felt really intense and exciting and like I was alive again. I came to my senses a few weeks later and blocked him off everything and I remember feeling so embarrassed that I had said any of that stuff to him, and that I wasn't in love with him at all, and I was mortified really that he now thinks I've spent years pining after him when really, I hadn't thought about him at all.
Then last year, I did the exact same with the other ex. Telling myself they were my soul mate. Obsessively looking through every old conversation, every photo I could find in my archive, stalking his social media. I added him one night in the midst of a frenzy and I woke up the next morning to see he had accepted and messaged to say how excited he was to see my name and to see how beautiful I still was and I felt these butterflies in my stomach for all of five seconds before I just felt disgusted in myself again.
Thankfully, I have enough self awareness to realise if I'm doing this to multiple ex's, it has absolutely nothing to do with them or any feelings I have towards them, but clearly the issue lies very much in myself. I started counselling at this point and was honest with dh about the issues we had in our marriage, as really it had nothing to do with these ex boyfriends but I just wasn't feeling happy or fulfilled in my marriage or in myself. It's so easy to sabotage everything and run to the excitement but those shiny men don't stay new and shiny for long and you'll remember all the issues they had soon enough.
No one is perfect, and sometimes when feelings are gone we need to be brave enough to walk away, but sometimes you can catch yourself in time and work on the cause. My husband and I are in a much better place now and have worked on bringing a spark back to us rather than chasing it elsewhere. I also really benefitted from counselling because I really did latch on to my memories of young love and desperately want to relive them and it really helped me to work through the reasons behind that and how to enjoy them as memories but not something to try and recreate.