Not counting non-consensual acts when I was a child, I've always been a pretty assertive woman. I'm sorry you have been in situations where you were afraid to speak up and say no. Sadly, so many women are taught to not say anything even when a man gets aggressive sexually.
I was always able to say no, and extricate myself if needed. I did have one guy call me a "ingrate bitch" because I wouldn't have sex with him. We weren't even CLOSE to having sex, he just suggested he wanted to "fuck" me and I said, no, I didn't want to. I never gave him the time of day after that.
I've been in other, less nasty situations. I just stuck to my guns if I didn't want to have sex with the guy. I figured it was my prerogative to say no if I didn't want sex.
Despite loving sex, when I was dating, I said No more than I said yes. I always had a certain type of relationship in mind and a certain type of man and how I felt he should treat me, before I ever considered having sex with them.