I think it's okay to reassure him it's not true you didn't want him for 17 years when HE brings it up without engaging in a lengthy battle about it. "I understand that you feel that way, and I'm sorry to hear that you feel that way. Especially because I have wanted you all these years and now." End topic. You need to get some be pleasant, don't allow him to mindread and tell you your reality, and walk away skills. It is very hard when someone is depressed and doing this but it can be done. Soon he will be all alone yelling at himself because he can't get you to fight him. It is very hard but possible. One way not to feel trapped is to give yourself permission to only give him a certain number of months to deal with his side of these issues before you refuse to have this stuff yelled at you anymore. View the situation as temporary. You are doing your best to work on this for a certain period of time and you will not do anything you regret just because someone else is acting weird. Good luck! Sounds like a rough time right now.
