My wife and I are both from the same town. After living in Denver for about a decade, we moved back to our hometown to raise a family. A girl that had grown up with us had also moved back and had a husband that was a pretty cool guy, so we hung out a good amount. She was always putting him down and insulting him in public. It was pretty uncomfortable for everyone, not just him. He is an oncologist - and a very good one - and she is basically just a rich housewife who goes through a bunch of nannies and au pairs because they always get fed up with her instability.
So after a few years, she starts calling people late at night and asking if they know about her husband sleeping with another lady in town. The other lady had had an affair in the past, but it was unlikely that this girl's husband had slept with her too. She basically just decided that he cheated on her - he didn't - and kicked him out of the house. She tried to get full custody of the kids but did not get it because he is a good guy and she is insane. So they split the kids 50/50 and he gives her everything: house, country club membership, child support, etc. I have talked to him about it. He said that he tried to reason with her but she was insane and threatening him with knives in front of the kids. He said that he doesn't think she is a danger to the children and basically feels bad for her. He tried to talk with her parents about it, and they know she is insane, but basically told him that they have no other choice but to back their daughter. This guy was trying to save the marriage.
So a few years go by and he starts dating another woman in town. She is young, very attractive and super nice. They take things slow and after about three years of dating, decide to get married. All of a sudden the first wife realizes that she is fat and alone. She has never had a job and just sits around doing nothing. So he gets married and this woman tries to sue his new wife for "alienation of affection," but the case gets dropped because the new wife didn't even live in the same state when they were married and didn't even meet the husband until they had been divorced for over two years. So she tries to sue the lady who she initially thought he cheated with but the statute of limitations was up. Meanwhile, the accused lady swears that she never slept with the husband and has no idea why she has been dragged into the mess.
So now the wife just sits on Facebook and writes nasty things about her children's father and his wife, nearly a decade after she divorced him for allegedly cheating on her. Everyone knows it didn't happen, including her. She is just insane.
It is sad, really. She ruined her life and has tried to ruin other people's lives. She has certainly ruined her kids' view on marriage, but the dad is a pretty stable dude who is working to make sure they are okay. Believe it or not, he still make sure to check in on the ex-wife regardless of what she says about him and puts up with loads of stuff that would send me over the edge. He maintains a good relationship with her parents.
Anyway, that is the only experience I have had with it.