Things to do, the two of you
Play daily challenges, work through question packs, leave a letter for them to open later, draw them something, or send a date invitation for your next adventure.
Play together
Games you take turns playing. Drop a piece, make a guess, nudge them when it's their move — a small back-and-forth that can run through the day.
Right on the home screen
Live on their home screen. A countdown to somethig special, or a doodle just for them — there every time you unlock your phone.