Which is why I am specifically recommending that episode by Dan Savage. It kind of highlights why emotional cheating shouldn't really be taking as a deal breaker in most case. He goes further to make a point about how actual physical cheating is also not the end of the world, but I don't totally agree with him on that one. This one:
http://www.savagelovecast.com/episodes/504#.V4-jOPmAOko
My point being, that doing this sort of stuff doesnt always lead to more stuff down the line and that just doing this sometimes just reinforces what your partner saw in you and highlights how you are so different than the other people. It is also sometimes done out of boredom, like masturbating just because you don't have anything else to do.