Coyoacan, I think the bitterness of a divorce/split often makes skewed thinking very common. People are able to convince themselves that they are doing the right thing even whilst the rest of the world watches on aghast. If you asked mothers if they would always act in the best interests of their child, I am sure they would instantly reply positively but the reality is, they are human subject to all the emotions that go with it and that has an impact on what they see as fair. I also think that having done all the work with pregnancy and birth, along with most of the nurturing, mothers feel they are much more righteous than the father. Even people I have admired greatly as parents somehow find themselves in this wrestling about the kids. I know that there were a lot of things I argued with my ex about to do with the care of the kids, things that were surmountable if we just hadn't been locked in intransigent positions. I look back and wonder why some of those things seemed so important. With age grows wisdom, I could have easily resolved some of the problems with some creative thinking. So yes, I think more often than not, the mothers subconsciously are trying to get at their exes and the 'protection' from their exes is usually a difference of opinion about the minutiae of looking after said kids.