((Garden)) Welcome to SR!
I'm sorry for your pain. It does get easier, I think. My A stepson (30 yo) has pulled every guilt-inducing, manipulative trick in the book on my husband. Mr. HG and I have realized that there is really nothing we can do to make his life go any better for him. We tell him that we love him and offer our opinion now only when asked. He is a grown man who will have to be responsible for the consequences of his actions just like the rest of us.
It is hard on a parent's heart, though. Sending hugs and prayers for you and your dear daughter.
HG