YTA - your daughter is going through a rough time and needs support, as a mother you should be able to console her, no matter what. She did not chose her father.

As a child from a broken home I can tell you that one of the things I admire most about my mother was how she never said a word about how shitty my father was. Children do not need to know this, they need love and care. You don't need to act like he was great, but should not vent to her about how awful he was or criticize her for spending time with him.

Sorry, don't mean to be an asshole and I can imagine you went through rough times, but you should always protect the children you chose to bring into this world before anything else.