Aw, Rig, you didn't do all that badly... you're in a very difficult situation, and anyway, this isn't about strategy and making the correct moves, it's about being vulnerable and honest. You showed that you care and that you're hurting. Nothing wrong with that. This isn't about pretending to be cool and indifferent. Just keep in mind one of the tenets of this BB (at least it's one of mine): you can't make anyone do anything. Which means you can't make her behave well and you can't make her behave badly. She is who she is and what you do doesn't change that. The fate and future of your marriage isn't riding on how you behave on any given day.
I'm sorry you're feeling so bad... but given the way your W deliberately yanks your chain, no one can blame you. She IS mean to you. You'd have to be a saint or a heartless robot not to react. I suspect she provokes you to reassure herself that you DO care. No finesse, but she does find out what she wants to know.
The best advice I can give you is NOT to get into these discussions at all. A while ago on this BB we used to refer to that sitch as your spouse jumping down in a pit and beckoning you to jump in there with them and "get into it." If you refuset to jump into the pit, then there can be no incident. If she utters one of those deliberately provocative statements and you can picture her standing in a pit full of alligators and waving at you to "come on down" maybe you can summon the willpower to walk away (literally or figuratively) and refuse to play the game.
Because it does seem like a game to me, a cruel game. She doesn't seem in search of real information during one of these incidents-- escept to ascertain that you still care about the fate of the marriage. She's pushing your hot buttons deliberately. I think you have to refuse to engage no matter how much she provokes you. You can say something like, "If you're trying to find out if I still care, I do, but that doesn't mean I'm going to get into a fight with you. I don't feel good after one of these fights, so I'm not going to get into it with you." And then end the convo, walk away, hang up, or whatever you need to do to NOT jump into the pit.
She is one very angry lady... when she spouts all that venom, can you pretend that she's speaking in a completely foreign language and that you do not understand any of the words but only hear the immense hurt and self-loathing behind the anger?
Recommit yourself to taking care of yourself. She probably feels like sh!t after one of these incidents, too. Actually she feels like sh!t before AND after... so you're doing both of you a favor by not engaging.