Happens a lot my man. Guys have got into these rooms/chat rooms/myspace..whatever and hooked up. Gals get into it saying that they are just friends and chatting,,whatever. Noone thinks that it's cheating because it's online and not personal. But as your friend found out,,it got personal quick. Online ppl can be whoever they want to be,,sweet,understanding,caring,whatever. Find your friends soon to be ex(hopefully) in a year or so and see if she is as "smitten" as she is now....almost sure she will be as unhappy as she is now..