One occasion. Attach as many files as belong to it. Or add several photos at once.
Shared money — joint accounts, transfers between you, shared purchases, bills, flights or rent one of you paid for.
Living arrangements — a shared lease, mail to the same address, staying at each other's homes, how you split chores.
Being known as a couple — photos together, time with each other's family and friends, events you were invited to as a pair.
Your life together — messages and calls, travel to see each other, plans you've made, knowing each other's world.