Oh I love the crazy ex stories.. here's mine:
Dated a girl from 15-20 not engaged.. thank god. She went from a little odd to full blown, bat-s**t crazy. We broke up, I got engaged, she started dating someone.
About 2 years go by, my fiance' and I buy a house get all settled and "ding dong" some random dude at the door. Evidently he was there to "kick my ass" (I out weigh him by 40+lbs and play 4 nights a week in a pro-fighting hockey league, he had a snowballs chance) She hasn't let it go, talked s**t about me constantly and claimed I was still leading her on and HE was there to "settle it"...
Scariest part... I never told her where we moved and I haven't spoken to her in the better part of 2 years.
What do you do in that situation? What did I do? I invited his gullible ass in for a beer, explained the world as the rest of us see it and let him check my facebook, cell phone and twitter as secondary confirmation to ease his mind. End of the day, he dumped her and we're still buds. Even came out with us for St. Patty's day.
You can't fix crazy all you can do is move others out of the way sometimes.