I voted other. There are some exceptions to the rule, as well as other circumstances.
I cheated on one person. That was 16 years ago, I will never cheat again. My husband (who is the one I cheated with) did the same thing. I know he will never cheat again as well. We were both in dead end marriages, sleeping in separate rooms and only staying for the kids... SERIOUSLY! We had also been friends for a few years, no bullshit involved. We finally gave in a month before we were each getting our separate divorces, yes we should have waited for moral/legal issues. We did not and 15 monogamous years later, we are still making it work, sometimes better then others, but we still love each other, are best friends/worst enemies, and will work as long as we love....should be a lifetime with the bond we have.
I am not trying to justify anything, but am trying to explain that it really depends on why and circumstances.