Relationships I can not stop thinking about a man that I can not stand?

I do business with a man. We fight constantly and sometimes he is nice. It seems like he only comes around when he needs something and if I do not answer then he calls repeatedly. we are both grown adults and he is married so I am against any type of feelings for a married man. For whatever reasons , I have impure thoughts towards this man and it sometimes consumes me. I do not want to feel this way . He lives in another state so we only talk , but have meet. How do I deal with these thoughts that wont go away?