I am a firm believer in serendipity- all the random pieces coming together in one wonderful moment, when suddenly you see what their purpose was all along.
It's a tough question, even in shows where you really don't think that there can be a romance plot, one gets worked in somehow. I was going to answer "1176", but you have John Adams' and Thomas Jefferson's wives singing and both sing romantic songs.
Even the flop musical "Billy", based on Herman Melville's "Billy Budd", worked in a flashback so that Billy and his girl could sing a love song.
"A coherent existance after so many years of muddle" - Desiree' Armfelt, A Little Night Music
"Life keeps happening everyday, Say Yes" - 70, Girls, 70
"Life is what you do while you're waiting to die" - Zorba
Tonya Pinkins: Then we had a "Lot's Wife" last June that was my personal favorite. I'm still trying to get them to let me sing it at some performance where we get to sing an excerpt that's gone.
Tony Kushner: You can sing it at my funeral.
Romance as in "love"? Romance to me also means adventure (the romance of the seas), or historical settings and action in romantic places, so it doesn't necessarily have to be the former. But, without some romance, would it be as appealing to most audiences?
In Spelling Bee the little crush between Barf and Olive is too cute - I suppose that's as romantic as you can get with kids that age!
I was going to say Five Guys Named Moe - do you consider the plot being centred around a guy who's heartbroken and pleading for his girl to return a romantic plot?
and how about Bring in Da Noise? or are we staying away from things like that? Like Stomp etc
Going through my playlist I came up with Billy Elliot (unless you count Debbie and Michael having a crush on Billy) [TOS] and Elegies for angels, punks and raging queens
"I trained as a classical actor at Juilliard. I jump at the opportunity to do classical text...But I never in a million years guessed I'd get to play Juliet!"- Michael Arden
And even though they tried to take it out, there is some implied romance between Bert and Mary in Mary Poppins.
Wendy and Tinker Bell both have some sort of romantic interest in Peter Pan (However, one could describe Tink's feeling as not romantic, more protective...because if he starts falling love he then starts growing up).
Cats has that dance between Victoria and the other cat.
I don't think I would count Assassins or Pacific Overtures. While both contain a song about "love", they are not romantic plots. In Assassins, the characters explain the motives behind their actions. In Pacific Overtures, a man is saying goodbye to his wife. Romantic plots are not illustrated or carried out in either show.
Most revues don't have plots of any sort, so they usually fit the bill.
"What can you expect from a bunch of seitan worshippers?" - Reginald Tresilian