As someone who has been at the crossroad you are at (I have 23 year old twin sons), I think stepping back is the best thing to do.

It was an extremely difficult decision for me, so I understand your concerns about this. There just comes a time when people need to learn lessons on their own, even if that may include a fall of some sort.

Don't get discouraged if things get worse between the two of you before they get better, and that may happen.

Good Luck.