Sounds like his medication needs some adjusting. My husband's anxiety/depression was managed with one medicine but another was added to help with the short temper and irritability. The boundary testing isn't going to magically end - especially if she can tell that he is avoiding her. She will learn boundaries with you but continue to test him. Ask if he'd consider talking to his doctor about his medications, even if it's for the short-term just to see if it helps
If he knows he’s acting this way I don’t know if you’ve spoken to him about it or not but it sounds like he needs different medication. Kids test you throughout life, no matter what age. Atm your child is going through something very big as often what happens around this age hence the terrible two’s is they are learning so much faster. It’s not the same for every child at this age but they want to establish their independence, they may find it frustrating if they can’t communicate fully which can lead to tantrums and anger. Maybe you could look into it with your partner and look at solutions or how to help each other and your child through it. If he is overwhelmed then you should ask him to step away from the situation. Sometimes everyone needs to do that so they can have some time to calm down
You are not being dramatic at all. I also thought my husband would be a way different father than he has turned out to be and he has broken my heart in so many ways. Do you think he would have made the same "hate" statement if not on the same meds he is now?