Same Apple ID for years never had this problem beforeAre you guys sharing the same Apple ID?
Only the right phone numbers checked not having problem with messagesThis is not really related.
One more place to check.
Settings-Messages-Send & Receive,
(tap on your phone number), make sure other phone number(s) are not checked.
There's your issue, is there a reason why you use the same Apple ID?Same Apple ID for years never had this problem before
16 years ago when the 1st iPhone came out that’s the way The Apple Store set it up for usThere's your issue, is there a reason why you use the same Apple ID?