Well, I'm a romantic, too, and if this were just a case of star-crossed lovers reuniting, I'd be the first to cheer. But I'm also aware that there's a third party--the ex's fiance--who likely wouldn't find any of this to be romantic. If the OP gets what he most wants, I hope the OP's ex handles her fiance's heart with as much care as possible.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher