I'm a little late for the MIL discussion, but mine is truly a gem. She frequently stops talking to DH because of some imagined insult.
Before he met me, DH was in a relationship with a woman from Panama. When he introduced her to his mom, MIL said right in front of her "I guess I won't ever have any white grandchildren, then."
We live in the same city, but we rarely see her. She came and took our cat away on DH's birthday without even wishing him a happy birthday, and DH hasn't even wanted to talk to her since. That was almost two years ago. I think we've seen her once since then, this last summer.
Me (40) DH (47) & furbabies * m/c 7/08 4/12 11/12