If you live in a western industrial.democracy, you are in your relationship voluntarily. (I'm sure that's true in other places as well, but just to cover bases...)

You are not a captive. You are not a hostage. You are free to leave at anytime.

This is especially, demonstrably true if you are cheating. Look at that....no one has you locked up! You're riding another dick/fucking another pussy!

The real taboo about cheating should be people trying to offer ANY EXPLANATION WHATSOEVER TO ANYONE.

The only acceptable explanation, because it is the only truthful one, is "I was weak".

The end.