BND....so much of the MIL stuff is common among all of us (with the rare exception of Angelica and others). I was shocked that the people who called me their "daughter" turned their backs on me within seconds.
Here's my theory....
When I told my parents of my marital strife, the first thing they did was ask "what do you think YOU did to contribute to this...change that, be better.." They did not care that I might be angry at them for saying that, they still challenged me. That is how I was raised. My parents cared more about the woman I became rather than worrying about what I though of them.
My H's parents care so much about their sons rejecting them. Their eldest son (BIL) already has. H has a short temper with is parents, and they are always walking on eggshells and will validate anything he does or his brother does.
I think they KNOW that they did not do right in childhood to their sons. They KNOW that they screwed up. They KNOW that it is a root cause of their sons actions in adulthood (my MIL is a child psych, for God's sake....how AWFUL...poor kids). I think when it comes to their sons going through hard times, and when they do the immature thing in pointing the finger of blame ALWAYS on something else, they encourage it ,b/c they don't want the finger to be pointed at THEM. So, sure, blame the W, the job, the location, whatever.....we will support you son, as long as you don't blame us....b/c we know that is the truth.
My IL's blame my BIL's new religion, W and her family for his rejection of them, even though he has made it CLEAR that he is rejecting them and treats them the way he does b/c of things they did. Such denial. Then, instead of saying "Son, we are sorry, how can we mend this..." They play victim to his antics....again forgetting they are the parents and need to address this as such.