So I was watching that Married at First Sight show with my roommate last night and had the sudden thought what of Character A signed on to a reality show to get married to a complete stranger and at the last minute like in full wedding dress/suit/whatever they go "what am I doing?!" And book it, runaway, knows there's gonna be legal crap with the producers with the contract and all, but "yeah no, I am not getting married on a reality show, sorry i was going through some rough stuff"
Then wherever they runaway to, weeks later they meet someone new and fall head over heels. Then one night is listening to Character B sheepishly recount the "dumbest thing I ever did" when they agreed to get married on a reality show and ended up getting stood up even then.
Que Character A going "ohhhh that me 😳"
I'm probably never going to write this AU but I'd 100% watch or read the romcom, so honestly? Man, imagine your OTP