Punkin, You raised a valid question...in many instances, they don't hate us. My xh would never come into the house when I was here. He would put stuff in the mailbox and drive away. I do think that at the time they are exiting from the relationship, they feel suffocated and hate the situation that they are in. They resent us, but I do not think that they hate us as people. They hate the fact that we are connected to what they think is an awful situation (by extension). If they truly hated us, they wouldn't come up with the "let's be friends" statement at a later time.
Punkin, there is absolutely no excuse in this world for what they've done to us, mlc or not. Normal, rational people would not be saying they haven't been happy for a year, two years, etc. I firmly believe that if our marriages were such a mess and unhappy, all of us would have walked a very, very long time ago. So, with that being said, it's not you, it's him and his need to grow up. You did the best that you could w/what you had to work with. None of us are mind readers or have crystal balls. They did not sit down and talk to us about their feelings until it was too late and they already had a foot out the door.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.