My wife always want me to write a poem for Valentine's Day, and I have done that before. This year, I didn't, but I did make a movie. I'm not sure if it's always available on Google Photos, but it was for this V-Day, so I used the tool under the Assistant. You need to choose two people and then it does the work of finding them together for use in the movie. So if you never take any photos with your special lady, this might not work.
I happen to have like 30,000 photos on Google Photos, so at least some had my wife with me. Not enough, really, but some.
If you click on the image below, and then click on it again once in Google Photos, you'll see the full-screen version with the music. All of this was done by Google finding us in the images. It probably also knows where we were, how old we were, who was there with us, and what we purchased while there. But hey, it's kind of romantic if you disregard all that. Be aware that Google will sometimes get the face recognition wrong, so you might get one with your wife and cousin thrown in there. Or you and your mother-in-law. So just review it before you send it.