Plenty of women and men masturbate whether they have an intimate partner or not. My girlfriend loves watching me, and vice versa, and yet we still manage to have a ton of sex.
It depends on the week for us I suppose. I do masturbate from time to time, but if I can have sex, I'll take that over masturbation any day. Sometimes we'll do a little of everything (dirty talk, sexy dancing, extended varied forms of foreplay) and beat around the bush so to speak before he dives into me...