Family Texting Issues

My family of 3 just switched cell phone providers and we all upgraded our iPhones. When we switched, we were all sharing one Apple ID. We had an issue with texts getting sent to one or the other who it should not have been sent to. So, we got each of us our own, separate Apple ID's. However, we are still having the same issue. When I text my husband, I put in his contact info, enter the message and hit send. When it sends, it automatically changes the contact info to my son and the message goes to him and not my husband. Some days, it's the opposite. Any thoughts on how to fix this? I've already checked Settings-Messages-Send & Receive and everything checks out there. Thanks!