Could he be facing some stress from your pregnancy and therefore he is distancing himself from you? While I agree that you should trust your instincts, but I think it’s good to get him to open up. You could try asking him in a different way, like instead of assuming he has another crush, you could ask if he is uncomfortable with your pregnancy and is there something that is worrying him. Sometimes, guys may appear to be cold when they are facing stress.
yes it can definitely be better than being in a horrible relationship. the torture and negativity can have a bad impact on the kids. sorry to hear you are going through this