How do you learn to trust men after you put so much time with another one that didn't really about…

How do you learn to trust men after you put so much time with another one that didn't really about you and like to make you feel like you are the reason things don't work no matter what you do? I have talking this guy for about 3 months now I felt he was moving to fast for me. He offered for us to move together to help us both out because of situation with my dad's wife not wanting me and the kids to live in the house any more. I told it was to soon to be living together because we have to get know other better. But in the back of my mind I really like him he excepts my kids but my heart says not trust him but my mind says trust. I have a hard trusting men. I trusted my son's dad but keeps going to prison and blaming me for him going. He is a manipulator. I tried for years to makes work but I finally realized he is not good me or my son. But in the mist of being made at my situation I had sex with a friend and got pregnant with daughter. I decided to keep her. But her dad has no interest in being apart of her life and I have except that it was my choice. But now I want to met the right man but I scared to let my guard down. I don't know what to do. The guy seems really nice he slowed down for me since I told him he was moving to fast. But I don't know how to held this situation any suggestions?