Parenting adult children

My daughter is 20 and her husband is 21. They have been married for a year.

My daughter is so mean to her husband. She’s controlling and treats him like he’s a child. She controls the money, their time, what he wears, his haircut, and on and on. I don’t know why she’s like that. Her dad was very controlling throughout our 18 year marriage, so I know that’s the example she grew up with. It was very hard for me to break away from his control and divorce him, but I had finally had it.

My question is how should I handle my relationship with my daughter? I know she is headed for unhappiness if she continues on the way she is. I feel like I should give her some advice or try to guide her somehow. At what point do we decide our children are adults and can do whatever they want? Is it appropriate to advise her? If so, how would I go about it?

We have a pretty good relationship, but she is even snappy and rude with me sometimes. I know that she knows the way she is acting is wrong and won’t make her have a happy marriage, but it’s like she can’t control herself. Help! It’s so hard to watch your child headed for disaster and feel like there’s nothing you can do to help them.