AIBU to think this advice often handed out is wrong?
I see women posting on here who are living with a new partner, and have kids from an ex. They often get no maintenance, in spite of trying to, or very little maintenance.
They post because their new partner refuses to contribute anything towards the cost of the kids living with them.
But the benefits system says that if you have a partner living with you, that they should be contributing towards the costs of the whole family, even if they are not your kids. So a woman with kids who has a partner moving in, may lose benefits because their new partner has moved in.
So yes he should contribute both because him moving in may lead to a loss of income for the woman, and morally you can not move in with someone and their kids and just say those kids are nothing to do with you.