We backed up both my husban'd and my phone to one iCloud accoun t. Now he gets my messages and I get his. How can we fix this?

Welcome to the Apple Community.

You need to have your own ID's.

On the iPhone[s] go to Settings -> Messages -> Send & Receive. You should be able to select which number and email address you want the device to respond to. Do it with Facetime, also.

You DON'T need to be on different AppleIDs. My wife and I are on the same one and we fixed this problem as I described.

Yes but it's only half a solution because you can't use your iCloud email address for messages.

Well, one person can, and it's probably just one person's email anyway. Yeah, one email address cannot be two email addresses but I don't think that is what she was curious about.

EDIT: So for me it's more like a 99% solution. Neither of us use our email addresses for messaging.

No, it's the email address for both of them, it's their iCloud ID.

I'm pleased it suits you, but it doesn't suit everyone.