there's plenty of couples that are amicably separated and take care of their kids fine, even some who still share a house (though not many tbh). besides it's still their fault for having kids without being sure they can handle the comittment then not being willing to stick with it.

Kid's'd be better off with a repressed parent, or an impoverished deserter parent, than a cheater. Cheating kills the trust in both parents, because the cheater becomes a disgusting liar and the one cheated on will likely be seen as too weak or otherwise unfitting, to be a good role model. Either way the child will doubt the value of the parents they even came from. That really leads to hell, for the whole family.