I'm a teacher for 12 years. one of my co workers has been my friend since the first day I entered school. he's a man who helps everyone and has many friends. I am married with 3 children and he's been married for 4 years and has one child. he always told me everything about his life.. the girls he dated .. the dates.. everyday events and almost every secret in his life. although sometimes we had some disagreements and little fights we never stopped talking to each other. my problem is 2 years ago he told me that he is in love with me. he wants me so much and for him I'm the only woman he wants in bed. recently he started touching me as if by accident and has admitted that he wants to have sex with me so bad. he dreams about me every night and especially when he's alone. he told me that he feels  sometimes that he wants to grab me and rape me. he has wild thoughts about me. i tried to cool him down but whenever we're alone he says that he prefers to leave because he can't control himself around me. he told me that his biggest passion is to have rough sex with where he treats me as a slave and ties me.  he repeats these words almost daily. he says I realy want you.. I want to feel you.. He loves in when I'm in pain or something hurts me. 

I am so scared! when I tried to block him in my phone he came into my class and yelled infront of the pupils that I can't hide from him. and that sooner or later he'll get what he wants from me. he was my one and only best friend at school. I'm trying to hate him but I cant because I also have feelings for him. I don't know what to do! please help!! I begged him to leave me alone because my husband will kill me if he knows but he didn't care.