Of course you wouldn't pay the bill of a casual boyfriend or girlfriend. This is different though, even though they are not married, they are in a serious committed relationship and have children together. In these circumstances he should pay in my view.
I believe most couples in committed relationships do try to help each other out if they financially able to do so.
Hmmm some do, some don't. I am one of the helpers and will donate money to my lovers etc, however the step dad will not and will not help my mum with money at all, in fact he will take it from her even though he has thousands stashed away, maybe Freeman is a tight ass