Like a lot of married guys, I had that one girlfriend who was sexually wild, but was also too high maintenance to marry. In my case, my ex-gf Lori had a crazy sex drive, maybe higher than mine. But Lori also liked to gender-bend some, and that helped me understand how much I wanted to have sex with other men.  

What started it was her wish to finger fuck me. She told me she wanted this out of the blue early in our relationship. We were just starting to get naked and making out, and she suddenly breathed into my ear that she wanted to finger fuck me. No woman had ever said anything like that to me, and I had no idea what to think. But I pulled my cock out and straddled her arm while she quickly pulled out her tits. She started stroking me and getting her fingers wet with precum. Her other hand went into her panties...