C.H.
Something is really wrong here and we can't possibly guess at that or the cure. Friends and family may know but not both sides so don't involve them because they'd never want to hurt your feelings or jeopardize a relationship with both of you if you stay together.
Get a good counselor. Find out why you're having marital problems, why your daughter is rejecting you, why you think it is okay for him not to spend time and attention on your son, etc. Your children's outlook on life and how to handle difficulties themselves ride on both of your abilities to problem solve. Even if you divorce, your and his problems will follow you and mess up the next relationship.
How to get a good one? That's hard. If friends and family have a good recommendation, try that. Ask your doctor or gynecologist. Ask for a cognitive behavioral therapist that believes in getting to the bottom of things, making changes, nad not spending years of dissecting your last week's issues. If you both don't think the person is going to be productive and handle things well, leave them. Don't waste time with them. If you can't afford it, there are organizations that can find the ones that will do it based on your income as they get some support from organizations. I wouldn't go for free counseling from your church. Keep your business to yourselves and not with people you socialize with. Besides, free isn't always good and it could make things worse.