I can say that Sue and I are the result of such a relationship... She was married, her husband left her in America and moved to brittain.
However, I feel there were certain mitigating circumstances that allowed Sue and I to work.
The first and foremost of these: Her husband mistreated her, and did not understand her.
The second: he was her first love, her first sexual encounter, and her first kiss.
Now, this meant that she really did not have a good reason to remain in the marriage which only lasted one year. Things have been rough between me and her lately, but I don't regret for a moment that I fell in love with her. I do regret that we let our passion get the better of us, and didn't wait until after the divorce to get together (which is unfortunately still in progress).