One of the great things about detachment is it does eventually help you step back from 'how could they do this' to 'what kind of person would do'. I think when you're reeling from the rollercoaster, it is hard to see the wood for the trees. Or to remember the normal bell curve of adult behaviour...we literally forget what normal looks like while we are trying to make sense of our spouse's words and actions.
It isn't normal or healthy to make life-changing choices without thinking of the effects on you and others. It isn't normal or healthy to create carnage and think it is someone else's job to tidy it up. It isn't normal or healthy to blame others for the consequences of your own actions. It isn't normal or healthy to hurt people and feel no need to say sorry or take actions to stop or make amends. It isn't normal or healthy to think that only your needs matter or to walk away from people who love you with no remorse or empathy.
People do it because they are not normal or healthy people. Might be just for a while, might be for ever. You and me couldn't do it, and that's why this stuff is so hard to understand, because we are essentially normal, healthy functioning adults. My H has been seeing a $350 an hour psychiatrist for almost 2 years. He claims this week that he has 'vanquished his demons' and gained 'insight'...evidentally not because his behaviour is still a million miles from a normal healthy adult, even one that has created carnage and is now trying to deal with it. What's that work out at? About $20000 roughly. If I were him, I'd be asking for a refund!
Me: 53 H:38 T:20 M:14 BD ILYB etc 10/15, H diagnosed severe depression S 1/16 PA 4/16 H filed 1/17