Emotions aren't logical and you have to start remembering that and use this small bit of info to your advantage so that you don't waste your time explaining how you've changed and that things will be better because in the end doing so goes against their feelings and they are in love with their feelings, telling them you've changed and you're different goes against their feelings which they love so much. Agree with them in everything even when they are attacking you, defending yourself against their attacks only forces them to put up their guards even more. Stop defending yourself, agree with them wholeheartedly, if they call you a horrible person, tell them that you are the most horrible person and you agree with them 100% and that you can't understand how they lived with you this long. The idea is that agreeing with them & their feelings lowers their shields, they'll continue fighting you if you continue defending yourself so you stop the fight by disarming yourself and taking whatever they give you (aside from verbal & physical abuse, just leave the room at that point with no response back to them).
Stop using your old logic to deal with their emotions, it never works. Be different, do different.
