How to over-come the fear of men & relationships?

I believe that this question has been asked before, but I am needing advice as to how to over-come my fear of men and relationships. I was once in a relationship for over a year with a man whom I thought was my “knight in shining armor”. I was engaged to him, and in the end- I had to end the relationship for I was giving more in the relationship then he did (financially, emotionally, and mentally-Yes, He turned-out to be a “user”). I also have a background where my father had deserted me for 10 years due to a wicked former-stepmother.
I notice that there are many men around me whom are single and interested in me, yet I “shy away” from them or try to direct their attention away from me. I know that it is not right what I am doing, that’s why I am asking for advice. Would like to know your thoughts. Thanks.