Hol, first off, it's an amazing feeling to care deeply for someone and I'm glad that you were able to find that in someone else even if you are now faced with a pretty physical and psychological dilemma.
I can see your point of view, you were open and honest with her about whom you were and your drug usage right from the get go, so it's not like it is a surprise that you were a drug user, she has known all along. You obviously know the depth of your addiction as you mentionedup front that if given the choice you would choose dope over her. You also know that this is not going to be an easy habit for you to kick. You can't stop using for anyone but yourself, so right off the bat you need to remove the thought that you are going to try to do this for her so that you won't lose her. It won't ever happen that way, and you know that. You need to do this for yourself and yourself alone, if that's even what you want to do at all.
I think while you may be angry or upset that this girl is making you choose, this girl has also shown some real dedication here. I don't know how long the two. Of you have been together but you told her straight up "I will choose dope over you" and yet she still stayed. She could have, and probably righftully, decided this was not a situation that she wanted to be in and took off, but she didn't. I think that her intentions while forceful, and are probably nott the best way to handle the situation, are coming from a genuine place. It would take quite a bit for me to believe that this girl did not care about you or your well being, I think she very much does. Wha she needs to understand is that she cannot force you to change, you are who you are (and this iss true of all personality traits) and she can either choose to accept it or choose to not accept it. That is ultimately up to her, and her alone.
I think right now the both of you are putting too much focus on the other one, both of you need to make some decisions about the future of this relationship for yourselves and you both need to think about your own set of expectations in what you want out of a partner. She needs to understand that she can't spend her life trying to save you, it's a futile effort. She needs to take some time and think about what she expects out of this relationship and rather than trying to make you conform to those expectations, she may need to take a step back from the relationship. You need to think about what you expect from this relationship as well, do you want someone trying to domineer over your life, even with the best of intentions? Do you want to get clean at all? If you don't, then you need to think about the future of this relationship as well.
Every relationship is going to be faced with it's own set of trials and tribulations, but you both need to find compromise, you both need to bend and decide what is worth working through and what is not. No one should ever be forced to live unhappily in the hopes that their partner will change. I think you both have a lot of thinking to do because this is a pretty serious issue. You both deserve happiness and need to decide for yourselves what "your own happiness" actually means and whether or not you can find it together.