>> To raise kids (in a responsible good manner), you need a long-lasting stable relationship with parents that are trustworthy and on the same wavelength.

Well it would be ideal but lots of kids have separated parents.

What is important is not that the parents are together, but that everyone is safe, the kids are loved, the parents are respectful towards one another. The greater the kindness and cooperation between separated parents, the better it is for kids.

Critically important is that the kids are not exposed to conflict between parents.

If you can get all that right then even kids with separated parents can be pretty happy I think.