Years ago I might have disagreed with all the “old-fashioned” posters and said that if he/she’s definitely separated, the estranged spouse is definitely crazy or abusive and they definitely will not be getting back together, then in that case it might be ok to screw around. But I had a situation that caused me to rethink that.
A woman I knew was no longer living with her husband. He was a total jerk who obviously didn’t care about her, was abusive, inattentive, they had gone through counseling, she had given him plenty of chances and he failed repeatedly. She told stories about him to “the girls” and they would shake their heads in amazement at his terrible antics. It seemed obvious their marriage was completely over except for the final paperwork, so I didn’t feel it was so wrong getting involved with her. Besides, in the lousy situation she was in, she needed someone to share good times together and forget about the past. I was happy to oblige her: we went out for meals together, spent a few nights together, took ski trips together, etc.
I was correct that their marriage was over. She had no intention of reuniting with him and eventually they did divorce. But what I didn’t realize was that, despite his neandrethal behavior, he somehow stupidly believed there was still some hope. I found that out one day when we walked out of my house and he was there in the street, furious, red in the face, pissed off that I was screwing his wife, and wanting to fight. I felt terrible. I honestly did not expect such a reaction. I had no idea he was following us and I honestly did not believe he still cared about her. But I was wrong. Somehow I was able to avoid a fight and I then backed out of that relationship as gracefully as I could.
Things aren’t always what they appear to be and the story one partner tells may not be how the other partner sees it. It’s probably best to avoid getting involved with a married person.