When is it okay?

I had an interesting/silly conversation with a young woman at work today. During conversation, she expressed her belief that it was wrong for a woman to sleep with a man who was engaged to another woman. As this is becoming a less common view, I was surprised. I decided to double check, and asked her if she believed it was wrong to sleep with somebody who was married. She replied to the affirmative, unless they were separated (so much for my high hopes). So I decided to have some fun, and it all came down to toilet paper. I asked if it would be okay to sleep with a married man, separated from his wife, if they lived in different rooms of the same house. She said that it wasn't. What about if they live in different apartments in the same apartment building. It was. Okay, what about if it's two apartments in the same house. It was. Okay, what about if the two apartments in the house share a bathroom. It wasn't. What about if there were two bathrooms (the apartments were now totally separate again), except that there was only one toilet paper holder for both bathrooms (there was a hole in the wall so that the two bathrooms shared a roll on the holder in the wall. It wasn't. What about if the man was separated from his husband. It was yuck. So, I left it there.