Not the father HELPPP

How do you tell somebody they’re not the father of your three month of baby? I just got the dna test back and he’s not the father but I’m literally soooo scared to tell him that’s he’s not I feel so embarrassed and humiliated he told his whole family this is his baby was there in the delivery room sign the birth certificate and had his other kids around my baby I can’t bring myself to tell him that he’s not the father 😓 should I just keep this secret to myself I’m terrified of what he would do to me(WERE NOT IN THE RELATIONSHIP ANYMORE we broke up the same month I got pregnant)