I am of a time when 90% of all men cheated on their wives to some extent and about 60% of wives did the same. Basically, for men the rule was one niters don't count. I think that STD and other factors have changed our morals and those percentages are much lower these days. I can recall that in the eighties the fear of herpes dramatically shut down casual sex for married men of reason and quality. AIDS was the final blow, (no pun intended).

Personally, I think an ongoing cyber sex relationship is kind of sick but there was phone sex before that and I have a hard time seeing it as justification to ending a relationship that had a prayer anyway. I do agree however that it goes beyond sexual fantasy and is probably worse than a one night stand, from the standpoint of jealousy alone.