Perhaps your heart is too big. You choose people that need "people" and you've tried to get out of that pattern but you chose "boring" people who just go through life, no depth of compassion, laughter.
You've never admitted it to yourself before, regarding the abuse. Now you have so it's a step, your eyes are now opening.
There is in-deed a code of ethic involved with Doctor, patient and there is in-deed a "next step" where abuse has been had, it never stops at pushing. Once a person knows they can do that, and get away with it, it's not enough anymore when they lose it, they need to do something more, worse.
He may be a great person "sometimes" stand by you, encourage you, allow you to be yourself, all that you have found there, is characteristics that you want in your life, for you... If you can see that, and the abuse maybe you can see that you are now soul searching for what is acceptable and what isn't, what you have and could still have elsewhere without the abuse.
If he can tolerate taking medication then he can tolerate seeing a Doctor himself that can send him to Anger Management classes, that can send him to a physcologist to help him get over his fears from childhood, abuse that he may have had himself... Until he can rid his past and forget his past, he can't move into the future anyway.
If you wont leave, that's your choice. You'll need four eyes, two in the back of your head, you never know what and when a trigger will occur...But at least talk him into getting everything under control, not just "anxiety" if that is what he has.....