Photos being shared across different apple ids

Is iCloud Photos enabled on all three devices? Are you using the Shared iCloud Photos Library on any of your devices for any of the three AppleIDs?

If you are signed into iCloud Photos on different devices using the same Apple ID, the iCloud Libraries from both devices will be merged into the iCloud Photos Library for this Apple ID. When you then switch to a different AppleID on this device, the photos will be merged into the different AppleID as well.

To fix the libraries and remove the unwanted photos, make sure that each of you is seeing all the own photos on their devices, then sign into a personal AppleID. As long as you are signed into iCloud Photos with your own AppleID that no one else is using, you can delete any unwanted photos from your device and it it will only be deleted from your own iCloud Photos Library. But you have to be sure, that the person who may want this photo has still a copy of it.

You can share selected photos with your family members, if you are setting up a shared iCloud Photos Library. Then you can selectively move photos to the shared library and all subscribers will see it in their library. This is very convenient, if all subscribers are considerate and are are only sharing photos that are interesting for all other subscribers and are not using the option to send each and every photo directly to the the shared library straight from the camera.