Some thing comes to my mind
When you assert your boundaries for the first time after being docile for a long time,people react very passive aggressive, they are angry that their scapegoat is trying to escape,they gaslight you how you are wrong in putting up boundaries,they take you on a guilt trip for not letting them use and abuse you,they will blame you of being selfish now that you want to protect your psyche, that you wanted to care for yourself.Essentially the abusers want to beat you down ,so that you will return to your previous position..That is...A scapegoat, or an emotional trash can.So that they can use and abuse you again.In their minds they are thinking...Ahhh I did all the hard work of identifying a nice target.You cannot be destroying that.Noo way.They desperately try to rehold on to you.
That is what happened with me when I stood up for myself.