Can’t find my wife in “people” on Photos

Photos may have merged her album with the album of another person.

• To find her People album, open some photo of her, where you previously have named her face.
• In the View menu enable the option "View > Show Face names".
• Try to find a phot, where her face is circled. View the photo enlarged, then swipe up to see the details below. Is there a faces thumbnail below the photo, perhaps of a different person, that is not in this photo?

Click at the icon of the face, to open this album, even if it is showing a different person. Are the photos of your wife in this wrong people album? Then try to separate the two merged people again. (How to Correct Merged People Albums - Apple Community)

If the thumbnail below her face is linked to the correct album, and you are seeing the correct photos there, look at the bottom of the open album for a command "Add ... to People & Pets" to add her album back.