In my W's case, it's because she's a very impulse-driven person, and, related to that, she has difficulty understanding a hypothetical scenario. She lives one day at a time. So someone can tell her "50% for the next ten years," and it just doesn't register the same way that it does others. Her brain is much more soaking up the emotions she feels today, her frustrations with our marriage and her infatuation with her divorced future. She also doesn't shift slowly between plans. Once a plan is set in her mind, it's set -- until there is some acute catalyst that makes her flip-flop.
As for MLC-ers and WAW's and WW's in general, I think some of this applies. They are just so sick of the marriage and so enamored with the solution (the divorce) that they fail to see the problems with their idea. They are self-focused, and their brain just wants to stop feeling bad. Even if it means losing 50% of the access to their kids. Plus if they have pot-stirrers and echo-chamber friends (divorcees) around them saying, Don't worry, kids are resilient, that helps them forget.
Me: 50, MLC/WW 45 Young kids Nov 2015: BD1 Apr 2016: BD2 Jan 2017: W filed Feb 2017: D final
