Is it normal to have the uncontrollable urge to fulfill sex fantasies??

For the last few years, i've had a hard time living. From family deaths to drug use to over-partying.
I got into alcoholic issues and got raped in my own house by a guy who was stalkin me with me even knowing.

Anyway.. im in a very loving and fulfilling relationshi but i find that sometimes i fantasize about having sex with this guy i met in the 4th grade but havent seen in years.. im nowhere near him but i still think about doin it, even if its years from now. i dont know why. this really isnt like me to think things like this.

i know i sound stupidas hell. i cant help who i am