What they say true?

How you know that people being honest. After 16year plus relationship ended. I realised I don't believe people. I struggle deeply with it. He would lie constantly, say what I'd want to hear. Mentally abused me and cheated through most of out relationship. The idea of moving on made me realise I don't trust anyone. How am I ment to move on with my life with a constant fear everyone is lieing. That they say only things to please you. Make you feel special just to get what they want. I want to trust others but I feel my old relationship I fear is going to effect my future friendships, relationships and love life.