Explain To Me These Facebook Reunions That Lead To Affairs and Broken Marriages...

Ummm.... Ok, so let me see if I understand this correctly.  There are people signing up for Facebook, finding old friends from high school, reconnecting with their past.  I get that, I have done it myself to an extent.  The ones I don't understand are the people that are reconnecting with high school boyfriends/girlfriends and then meeting up and rekindling romances, quite a few breaking up marriages...  I had heard about this before but recently I had an up and close front seat to it.  I accepted a friend request from a girl (because in my head she is still 17), I sort of remember her, so why not.  A few hours later she is posting like crazy about someone she's madly in love with (her info says she's divorced) and as the comments follow, the object of her affection is another alumni that apparently is still married and acknowledges they are "in love and boyfriend and girlfriend"....  Umm, does your wife know?! Here's the big thing that my shallow self cannot grasp.... (oh, I'd like to add that I did quickly delete this girl/home wrecker, not my cup of tea) How is it that the two of you weren't hot and heavy in high school, but now, 20 years later, years that apparently were not kind to either one of you (umm, not to me either, 20 years affects all of our elasticity and firmness.) I mean, he has lost his hair, has found at least 50 pounds, and you can't stay away from that fine piece of meat?! I mean, not even taking into account the marriage, the children that you are about to irreparably damage for life, just the shallow parts.... What on earth is rocking your boat?!  I'm sure that you feel like your marriage failed, what's another, and damnit, you can't fight love, but give me a break.... He's not the same boy you knew and the baggage just isn't worth it.... My guess is you'd rather be back in the life you led in 1989.....  I hope one of your FB friends emails his wife.....