As to the search function I give a thumbs up on future development, if possible.
In the meantime, I did the following as a work around. There is some work involved, but you can achieve the goal and only need to do it one time.
I wanted a list of all the photos in my library where my wife and I were together. I first went to the people tab and selected the one of us that had the highest number of occurrences. This insured all photos of the two of us together in my library would be picked up. I then “selected all” of the photos with this person and clicked the favorites button to move those to favorites album.
Next, I went to the favorites album and removed all the photos that did not have the two of us together.
Lastly, select all the remaining photos in the favorites album (these are the ones that have both together) and added a tag, such as “John and Sally”.
A “John and Sally” tag is now always in the “Albums” tab if I want to view those photos now or in the future. Only drawback to this approach is that you need to remember to add this tag to any pictures you add of the two of you to your library in the future.