With one gf, we broke up and the very next night she had one of my friends I knew for 10+ years over 'comforting her' and he was married for 2 years at the time to a nice lady and I was bestman at that wedding. So not only did I lose having any kind of friendship with her after the split, but also lost a good mate because he was a scumbag.
And, my ex-girlfriend. We broke up late last year after 2.5 years. I went over to her place and it was unusually tidy (her house is usually a mess) and I noticed 2 empty wine bottles on the floor, from her activities the night before with a 'male friend' that she had over.
Instead of resorting to alcohol, drugs or comfort food, I try turn it into positive and continue health goals at the gym and try move on.