There is a sexual difference with respect to what bothers the spouses of cheaters. Women are more bothered by emotional affairs, and men are more bothered by sexual affairs. As a generalization with many exceptions, of course.
I was living with someone else when I met my wife. My ex asked to meet my future wife, and they did meet. I wasn’t there, but I think my ex asked my future wife a few questions about what we did.
I also had an affair or two later on in my marriage. In one case, the husband found out, and kept questioning my lover over and over about what it was about me that was different from him. He kept trying to be like me, she said, which, of course, is impossible. Not because I’m anything special, but because you can’t be like anyone else.
So I think the urge to meet the other woman or man is about understanding where your relationship went wrong. What does this person have that I don’t have? How could they leave me? How can I get them back?
My wife got me back by taking my to a shrink and having me diagnosed with a mental illness. That doesn’t excuse what I did. But I think it helped her tell herself a story that allowed her to stay with me. At the time, I would have been happy if she would have kicked me out. In fact, I was hoping she would.
We also got counseling. The counselor suggested we both were to blame, and that we should agree to that and move on to solving problems so that we could stay together. We both accepted half the blame, and found subsequent counseling to be very helpful. But it’s still a work in progress, and probably will always be that.