Oh boy, sounds like some AirDrop tomfoolery.
When you tap person from people, every one of her devices that is in range and unlock should receive a notification to accept or decline the air drop. She can then choose to accept it from which device she would like. When I send from my work phone to me under People (different AppleID's for privacy) I get a notification on my iPhone, iMac, MBP and iPad all at the same time...its weird but I rarely have all of them on at the same time.
Below people you have devices, those are YOUR devices or at least should be. This is for you to transfer files between your own devices.
Good luck getting this sorted out, head hurts thinking about it. What I can say is go into Settings > AppleID (your name at the top). Scroll down to devices and make sure those are only yours, if there is a device you don't use anymore especially if its shared then remove it and have the person using it use their AppleID. Then scroll back up and tap "Name, Phone Numbers, Email" make sure those emails and phone numbers are yours, remove emails and numbers you don't use.
Then do the same to her phone. I'm sure she's not fed up with you messing with her phone by now...lol
If you guys are sharing Apps then set up a family plan. It gives BETTER benefits then sharing an AppleID IMO. Hopefully those apps are still available in the store for download.
I had a shared email address between both my personal and work AppleID's and for some reason this carried over a lot of data. I wasn't logged into anything with either address it was just an extra but since they were shared it associated my full name, address, phone number, profile picture, etc...Again this email wasn't being used to sign into anything it was just on my AppleID as an extra one. Once I removed it from my personal account the work account forgot all that data. Unfortunately I didn't try AirDrop but there is a good chance it would have associated that email to me and made the work phone part of "my devices".
Hopefully that helps some. Good luck!
