I'm sure all of these above reasons, and many others not listed,might be reasons given as towhy *anyone* would make the choice to cheat. It's a big world out there after all.
The first one listed as 10 is just flat out dumb - it's not cheating if it's not an exclusive relationship. Obviously someone polled on this thought it was though....
Editing in an attempt to clarify that I think any reason is a poor one. Sounded like I was condoning cheating when I re-read. Which I'm not!