The personal relationship doesn't exist, and he never cultivated it with the child. If the child is his biologically, he should contribute to the support of the child (not teh support of the woman). If the child is not his biological father, and he never established a personal relationship with the child, then he isn't respobsible in any way for the wellbeing of the child.
If the man leaving the marriage has a relationship with that child, then why should the mother's decision deprive that child of a 'father'?
It doesn't. The child has a father even if he divorces the child's mother.
Why is it you only want to apply this to children living with their supposed biological father? If it's all about feelings, why embrace an arbitrary and inconsistent standard?
I don't. It would apply to any adult male who presented himself as the child's father, even if he is in fact wrong. I don't see why you interpreted my comments in such a warped, self serving way.