Nice men want to murder me.?

I am in college and I have been dating. I was raised to choose guys who were nice, intelligent and respectful & those are the type I like. However, everytime I get a nice man I think he may be perhaps planning to murder me. I am afraid of men and I somehow always back out of relationship s out of fear that he may do something extreme to harm me. It s not that I feel getting my heart broken and I don t have a case of broken trust because I have never been cheated on. It s different from distrust in a relationship, it s more like a fear of nice men. Every time I m with him my mind travels and I start positioning for just incase I am attacked. I know he won t hurt me and that s what I want to believe he isn t trying to murder me, but I can t. U just want to be free to love. Should I see someone? What us happening? Is this normal? Can someone try to explain what s going on?