[Jess~]

go to therapy. get help.
it's important that you realize this is a problem, and i'm proud of you for having the courage to reach out and admit that you have a problem.

first of all, stop putting drugs and medications that she doesn't need in her drink. that's just wrong on so many levels. if you'd like to suggest she take a certain supplement or treatment you can talk to her, and then she can decide whether she wants to take that pill or not. but you cannot make someone take something like that without their consent.

if a partner says a position is hurting them and asks you to stop and you continue, that's actually a form of rape. if you respect your girlfriend in the slightest you will respect her body and what she wants/doesn't want done to her.

i think if you can't get into therapy, the least you can do is talk to your girlfriend. tell her you're sorry for acting out like that and that you don't want to hurt her. if you truly can't stop yourself from doing those things, you shouldn't be dating. you should be taking this time to develop yourself and deal with any internal struggles that might be causing you to be so violent.