Raw sexuality is a primal force. Like rapidly running water, it carves channels through paths of least resistance. Ultimately however it's shaped by our life experiences and our cultures.
Taking a page from RAW, determine what your first orgasm was like. How similar is it to previous orgasm experiences, has it shaped every sexual experience for you from that point onward?
It's entirely probable that the desire for femdom comes from a time when your mother or mother-figure in life made decisions for you. She was probably stern and paternalistic, but took care of your needs. Your father was probably estranged from your family or was otherwise not present through your life, or otherwise not considered a strong masculine figure. Or I could be completely wrong, make room for doubt. My point is that these figures in your life shape your idea of the masculine/feminine archetypes in your psyche.
Anyway, a compulsion to fap and experience something like femdom reveals some deeper attitudes formed earlier in life as well as your current outlook and experience. You may need to engage what RAW called the "oral biosurvival circuit." Chronic fapping comes from a need for comfort.
Instead of masturbating or even sitting there on the computer, start to make your life more stable, do more physical activities, not just exercise, but relaxation like yoga, massage or a trip to a spa. Take up meditation if you haven't already, and look into slower tantric sex with your gf. if she's not into it, maybe examine where your relationship may be causing your problems.