The fine line

The medicine I am on stretches beyond the normal boundries of hormonal arousal and desire, and I've done something that straddles the fine line between a rape scene and actual rape. I'm not proud of this fact, and I intend to find a way to prevent it in the future (suggestions appreciated). However, it is something that I wish to share, since I can't take it back.
My lovely wife and mistress enjoys a good rape scene, but she does not enjoy sexual abuse. I feel that I have crossed that line in such a way to be abusive without pain, but with dominance. I awoke from dreaming about extremely erotic sex with her and lost control of myself. She was still sleeping, but my hands did not stop with myself, but I began uncontrollably fondling her. I brought her nipples to full attention, and fingered her crotch until she was gyrating her hips uncontrollably. I wasn't sure if she was aware of my ministration, but later found that the fingering woke her. She was at this point so hot that she said "the option of refusal had been taken away". She needed to cum so badly that she unwillingly welcomed my thrusting member.
I am still unable to orgasm without her, but I was able to cum inside her by this method. I started this while half awake and she was asleep. It was pure instinct, and was fueled by raw desire. However, I love my wife, and though she has said she does not consider this rape I feel that it straddles that line. She was not happy with me for doing this to her, and for that I'm truly sorry. I did ask her to refrain from punishing me, since I do not feel that I had a choice in what I did to her either (though I do take responsibility). She did, of course, point out that there is no reason I shouldn't be punished for it, so I suppose I am in big trouble.

To my wife, the most wonderful woman on earth:

I'm sorry sweetheart. I love you and never want to hurt you again.

Love,
Your husband.