There are wishes for marriage, breakups, moving in, cheating, almost every interaction in the game, but not to become a Sim's partner in the first place as far as I can tell.

I like to play according to loose wishacy rules, but I always have to choose when to take this one step because my sims will not do it on their own.

My sims always chose their own partner, I never 'make them' do anything actually I play with full autonomy on, always, and I use the mod by bluegenjutsu "Auto Romance up to propose Marriage Break Up Divorce" which means sims will autonomously propose going steady, engaged, marriage and divorce (if they made a mistake ) to sims they are attracted to.

https://simsasylum.com/tfm/index.php

You'll find this mod here, sorry I can't link the exact mod (I can't remember my password ) but it wont be hard to find, just look under the creators name. You need to register first.

There are many flavours to this mod, read carefully, you can always change to another if it doesn't suit though.

The other thing to note is that sims with the "hopeless romantic" trait, do (and often) roll the wish to "fall in love with", "Go on a date with" and other cutsy wishes, if that's what you're after just give them that trait, and flirty, and they'll be married in no time They don't always make the best choice though *spoiler alert*

Combine this with some Nraas mods, Story Progression, Story Progression Relationship, Woohooer, as a suggestion, and you can make your relationships much more autonomous, and interesting