Having trouble with my girlfriend meeting my emotional needs

It would seem that over the course of mine and my girlfriend’s relationship, I’ve developed certain sexual proclivities that she is having a hard time understanding. It started out normail, with light slaps to the rear end, and punches to the small of her back, pretty vanilla stuff that most normal couples experiment with. Lately though, I keep attempting to go further, but she always resists. I always promise that I’ll keep it “friendly” but the closer and closer I get to climax, the more I cannot resist the urge to close off her windpipe with my hands. She has no concept of why I would attempt to do this, and has warned me that if I try it again she will be contacting the police. Since then, I have absolutely not been able to orgasm during normal sex. The closest I came was without choking her was last week when we were making love and she fell off the bed and cracked her head on the nightstand. There was a small amount of blood, nothing serious, but just seeing her in such pain was totally arousing. I don’t know who else to ask about this, since I don’t want any of my friends to think I have any actual problems, but is there any option other than leaving her? Had anyone else been able to deal with their significant other not being compatible sexually?