Sexual Dream

So something weird happened to me that has never happened before. I'm in a happy relationship with my fiance but last night I dreamed of sex with a complete stranger and then that stranger just so happened to be friends with my highschool boyfriend from 7 years ago. I have no feelings for this guy what so ever because he left me for one of my best friend at the time. He then came back to me after she dumped him. When she came begging for him back he had no problem leaving me again. I know I was a teenager and naive. I mean he and I occasionally talk over Facebook just to update each other about our lives and old times before we dated but he is in a committed relationship and so am I. That's usually once or twice a year. We have settled our issues and are now acquaintances. I no longer feel anything for him when I talk to him or anything. My fiance and him are more friendly to each other then I am to him. So I don't know why I had a dream about sleeping with a stranger or why he showed up in it. Also I woke up really turned on and no matter what I do I still feel turned on. please help I've taken a cold shower. I've tried to watch TV etc. My fiance is across town at our best guy friends house and I'll be going their soon but not like this :/.