The problem is that , legally, it is only DH who is liable for any costs. But because of all the activities and expectations, I am paying for them too. Now, I don't actually mind as I view it as 'our' money, but their mother expects it. And that is ridiculous. It is just not sustainable. Hence the lawyer.
Yes, we also told her that we would no longer be covering costs at her house, as she does not cover anything at ours during our time with them.