You can take these suggestions alone or in combination, use RNG to help you choose, or do whatever you want! Just have fun.
All the descriptions are intended to be as neutral as possible, and please don't let them discourage poly, harems, or anything your heart desires.
1. Tag with your character/fandom and preferences. 2. Someone tags you with a scenario. 3. ??? 4. Profit!
#1. And Wuv, Twu Wuv... - Whether you've just met, or been together forever, you've finally decided to take that extra step in your relationship. You're soul mates, best friends, lovers, and you want the world to know it.
#2. Shotgun Wedding - Maybe there's a baby, or you accidentally slapped that person with your right hand, or you proposed while drunk and their family's holding you to it... you're stuck, friend. Step up and say the words... and make the best of it?
#3. Matchmaker, Matchmaker - It's very possible you have never seen your intended until five minutes ago, when you were joined. Or, maybe you've had a little time beforehand, when your parents/boss/king introduced you. You saw them in a catalog (or they saw you) and the plane is now arriving. Maybe you've been betrothed since birth and you couldn't be happier to be marrying your childhood friend.
#4. Do Me a Favor.... - Is there a rule in your company that you can't get promoted unless you're hitched? Perhaps you're getting on in years and you'll be a social pariah if you're still single when you're thirty. Do you need to get your "green card"? For whatever reason, you need to get married, and this person saying "I do" with you has agreed to help you out.
#5. It's Money, Honey - Your intended is stinking, filthy rich... and you're definitely not. They might be downright odious, but you don't really care. Maybe money can't guarantee happiness, but you will take that risk.
#6. Just Play Along - Are you marrying into the mob to get information to bring them down? Or is it part of both your cover stories? Something about your marriage is fake, and that's okay, as long as no one finds out.
#7. Newlyweds - The wedding's over! Now it's onto the good part -- the honeymoon. Where are you going? And what are you going to do when you get there?
#8. Together Forever - You've had that ring on so long, you're not sure it'll ever come off. Is someone else getting married? Or is it your anniversary and you're looking forward to another year of waking up to your partner's beloved face?
#9. Entangled Oak Trees - Maybe you bicker constantly, or one of you can't even hear the other anymore. (Or maybe you just behave like a pair of old crows who've been together so long, no one remembers you ever being apart.) But it's been the two of you through thick and thin, sickness and health, richer and poorer.
#10. No One Said it Would Last Forever - No matter how much you might have wanted it to, it just didn't work. Or things were lovely, but it ended too soon. Or, maybe, you part aimiably, find other people, and still get together for happy hours on Friday nights.
#11. Wedding Roulette - Whatever scenario tickles your fancy!