Okokok nailed it. I'm a contrarian poster here in that I don't agree with the old saw that a BS having sex with somebody other than her/his WS is "bringing her/himself down to the level" of the WS.
I do agree that if it's done for some sort of "revenge" against the WS, it won't work. The BS will never hurt the WS the same way the WS hurt the BS. I also agree that it will profoundly change the marriage dynamic, usually in ways that are quite unpredictable.
But I completely empathize with the feeling of "he/she had his/her fun, I want to have my fun." If opportunity knocks, go have your fun. Just remember that once you set a series of events in motion, they will ineluctably continue to their natural conclusion.
Like Okokok, I was dumped by my wayward, so I was newly single and young and professional and I had some wild years. I had plenty of fun. Like Okokok, I did some pretty sketchy stuff from an ethical perspective, variations of future faking and half truthing to get laid. I regret a lot of it now and, looking back, realize that I was a broken man doing broken things.
I even got a modicum of revenge. A year or two after she dumped me, she dropped a few hints about the possibility of giving us another go. I made it a point to show up at a social event that I knew she would attend with a date who was exotically beautiful and smoking hot and who was way into me at the time.
In the end, none of the "revenge" stuff made me feel better. The new sex was fun and did make me feel better, but it was temporary. I didn't really heal until I stopped sleeping around and started focusing on making myself healthy, both emotionally and physically. I don't think it's an accident that after about a year of that, after truly finding my own inner peace, I then met the woman who is now my wife of almost 25 years.
