kids and money

It sounds as though it may be best to keep your finances completely separate. Your kids are adults, so parenting shouldn't be a huge role in your relationship, but if his son never really figures out how to grow up then that will be a huge problem. If you can't agree on how to manage money with your children, then the best advice I can give is to agree to disagree, then use your own finances to support your children and stop resenting the other person for what they have or choose to give to their kids.

Your daughter is 24, assumedly in grad school. If she is a responsible adult then she can pay for her own books because she should have a job. I understand that you want to help her, but it sounds as though your desire to help your kids through school also stems from a desire for them to use you as a financial resource instead of their father.

"What my children are learning is that they can count on Dad when they need money, but not Mom"

Your ex can afford it, so let him. Money shouldn't be the crux of your relationships with your children.

I wonder if your DH's opinion has to do with your DD's behaviors.