"when it doesn't happen like that there are all sorts of...

"when it doesn't happen like that there are all sorts of judgements on the separated couple etc."

Don't you mean when it happens there are all kinds of natural consequences on the couple and God forbid, their kids? (OK, maybe 50 years ago there would be societal judgement as well, these days it's so common place that you might get some sympathy if you're lucky but I haven't heard of people being judged down any more.) Take a look at pretty much any negative statistic you want, promiscuity, crime, drug abuse and you'll find that in over 90% of cases there is an absent or abusive father involved.

One of the things that makes us different from the animals is that between stimulus and response we have the power of choice. You don't have to marry/breed with the wrong woman/man, you don't have to wallow in self-pity because you're stuck in a bad relationship. You don't have to refuse to grow up and meet your responsibilities. You can man-up and get the help you need to make the changes to turn the relationship and consequently everyone's happiness around. Or you can wuss out and abandon your family. You don't have to have affairs and fantasies either. All these things are your choice, choices that animals don't get to make. Of course it takes 2 to tango and if it's your partner that's carrying on like then and doesn't want to change then same result. (Still your fault for choosing poorly though. :) )