WHY? PLEASE NO BASHING.

WHY in the world do i want to have sex SOOO bad with my boyfriends cousin. We are the same age i have 2 kids he has a kid. Were both young 20 years old. We use to have a little fling we fulled around madeout ALOT etc everytime he comes around i am always happy, we have never slept together he told me not to long ago hes had 2-3 dreams about us having sex, and so have i. I feel horrible i dont know what this means or what mine or his dreams mean BUT it is driving me insane and its not like me and my SO dont have a good relationship because we do we always have sex, normally if i start it. I never get ate out or cum. Never get touched down there, I haven't 'came' in years. I have tryed talking to him about it but nothing changes. Please help me understand why i want this so bad with his cousin. Of course i would never do it but i want to know what these dreams could mean and why i am having them?

SORRY i just posted in the wrong group!