Face recognition in photos

I've been wanting to make a proper catalogue of my familys photos for a while now and I've been lookin for a good way to index who are in the pictures. I just recently discovered the face recogintion tool in the "Photos" app, which seemed like a dream come true, until I realized that whatever information I added didn't stay liked to the photo if I tried to moved it. I have roughly 400 GB of family photos, not counting 25 years of negative strips and slides that I am currenty only scratching the surface in my process of digitalizing it all. That is far too much to store on my 500 GB computer memmory, anyway I like to have at least two backups on seperate external hard drives. So I need whatever information I add to stay linked to the picture when I move it from my computer to my external hard drives, or all the work I am about to put into this will be usless. I tried with a handfull of images already, and when I tried to move them the names I'd added stayed on as keywords, but nothing to indicate who the name belonged to, and when I tried to import them again to "Photos" on the very same computer the markings I'd placed at each face was gone. Is there any fix to make this work the way I want to (or any other programm to do this with). Preferably I'd want it to be translatable to software used by windows-users as well, so that I could share pictures with relatives that don't use Apple products, but if there is a fix for my problem with the information staying linked to the photos I can live with it only being a Mac/Apple thing.