I'm not easy to sleep with when I'm not dating you, but if I'm in a relationship with you... Yeah, I tend to get that way. In high school, I slept with one guy my sophomore year and the rumors flew. He started lies like "She slept with four different guys while she was with me," "She's secretly bisexual," and my favourate, "She has HIV, and she didn't tell me until after we had sex." Needless to say, none of the guys believed the HIV one, but all of the girls did. I didn't get a moment of peace my whole Junior year, between the girls spreading nasty things and the guys constantly hitting on me/sexually harassing me. By senior year, I had already given up hopes of proving them all wrong, and my self-esteem was out the window. I made my slutty/bisexual reputation come true, and half of the guys in the school found out where my birthmark is firsthand. The other half was either a bunch of prude assholes or they were dating a girl they knew would try to kill me if they slept with me.
I was easy, and I learned the hard way that it doesn't solve anything. The rumors got so bad about the HIV thing that my aunt heard about it and had me tested for everything. I came up clean, but she still made me get tested every six months. It was annoying, and the rumors still kept going. I stopped being easy halfway through my senior year, and I think I sent almost half of the male student body into an onslaught of depression and angst.
I guess I matured enough to know that it doesn't help, but I don't think the being easy came from my personality type. It was more likely the being abused for years and lack of self-esteem/respect.