Wanted
Idea sent by Patito.
Let me tell you about a detail I did for my boyfriend to surprise him:
On the computer, I created a sheet with his photo and the sign 'Wanted' (like in Western movies). Below the photo, I listed all the reasons I fell in love with him. For example, the sign would look something like this:
WANTED
The photo would go here.
1.- For being the most wonderful man in the world. 2.- For loving me so much. 3.- ...
If you need some inspiration for your poster, you won't have trouble finding images of 'Wanted' posters in Google or any other search engine.
I hope this idea is useful for surprising your partner.