GF has sexy but boyish body, satisfies my bi-desires

I am 20 year old male, in good shape and I have had sex with other men and of course, women. I find m2m sex urgent, lustful, and immediate. I am top only in m2m sex. I always liked very very femme people for sex partners male or female. My current GF who is 22 lives with me, and is perfect. She has natural blonde hair, a very boyish body, straight at the waist, almost 0 tits, great legs and a pert ass. Her natural blonde pussy hair is a plus too. She knew about my having sex with other guys on occasion, usually when out of town, or just needing a quick release. In fact she and I met, as I was coming out of her brothers room at the apartment they shared at the time. Her brother is a gay bottom, who quite frankly looks just like her. We dated, and before we discussed exclusivity I saw other women, and she other men, and I also saw men on occasion. Mainly to get sucked off, or have a quick fuck, never any emotional attachment.

Deb, my GF wanted to be exclusive after about a year of dating, she knew that I had during our dating even fucked her brother sometimes. She honestly didn't care about that, but she didn't like me going with other women. So our initial exclusivity was based on me not being with other women and her not being with other men. I still had some m2m sex. After asking details I told her that yes, I did get fucked by one man when I was 16 several times, I sucked him also, and decided that wasn't what I wanted. I am the top, I tried bottom and it was a big NO. When she agreed to live with me, she said that she had a way of satisfying my m2m top need. Deb has very short hair on her head, and as I said a very boyish body. Every weekend, she dresses is jockey undies, singlet tees, jeans and tennis shoes, she combs her short hair different, and we have anal sex. She being the bottom boy, and me being the top man. She will suck me and lets me fuck her in her ass. Her nerve endings must accumulate in her butt, after about 5 times she can actually cum from getting buttfucked. She talks like a boy, dresses like a boy, and sexually acts like a boy.

I'm a very happy bi guy with my wonderful girlfriend who is also my boyfriend.