contact splitting phone number and email into two separate iMessage chats

Hello. I have been searching through this thread endlessly trying to figure this one out as I’ve never had an issue like this before. It’s pretty much as the title says; iMessage is registering my email as a contact all on its own and whenever my husband tries to text me it splits the chat from the phone number into one, and the email in the other. And it gets better — when I text him it comes from the phone number but he can only text me in the email thread! It makes no sense. I have disabled email from my send and receive in settings and I’ve tried deleting my contact, the chat history, popping the SIM card, but nothing seems to help.