cheating

i recently found out i was pregnant, 3 days after my boyfriend and i broke up. he acted great until he changed and then he moves in with his ex girlfriend and now says they’re getting married. i am trying so hard to be positive and happy about this baby but im so heartbroken. we used to talk about marriage and living together and it was great. and then he stopped talking to me for 2 days and announces they’re back together. he doesn’t want anything to do with me until he gets a dna test. i never cheated. i tried my hardest to be the perfect girlfriend all while he was messing around with his ex. and now im terrified of miscarriage because this is the only thing i have left of him, and the only happy thing (besides my daughter) i have. can someone please tell me its going to be okay. everyone keeps saying theyll break up and not to worry. but what if they don’t. i love him so much. and i miss him. this isn’t fair.