I want to sleep with my male cousin
Why would you want to sleep with him?
I want to sleep with a person whose related to me
It's gross to have a relationship with your cousin. You should only date people that aren't related to you.
I just have single family issues with my family because my parents are gone.
That is even more reason to seek out some professional help, there is nothing wrong with getting a therapist. Life will be easier and you won't have such disturbing thoughts about such a thing while under a doctor's care.