Greetings,
I haven't seen Leap Year yet, but I recently watched (for about the 4th time) The Wish Lis, which is about a woman who meets two men at the same time, has chemistry with one but becomes fianceed to the other.
Here's the plot summarys from IMBD:
The Wish List (2010) (TV) More at IMDbPro
After several nasty dating surprises, instantaneous HR executive Sarah compiles a 'complete' list of potential partner requirements. After handsome pediatrician and perfect gentleman Erik meets all criteria and charms her family, wedding plans are soon in the making. Yet one impish voice nags at her, that of LA "barista" Fred, who swears by surprising his customers and usually succeeds. Fred's reproach her drawings show talent but no ambition inspires her to try a fresh style, and she enters him for a national competition, while Erik smoothly keeps doing everything 'too' right. Written by KGF Vissers
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Oh and here's a good one I enjoyed...fianceed woman who falls for another guy:
The Seven Year Hitch (2012)
Two best friends accidentally take their relationship to the next level and suddenly find themselves saying 'I do.'
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And if you like the classics (I know I do) there's this:
It Had to Be You (1947)
Ginger Rogers always gets cold feet just before four weddings until fireman Cornell Wilde appears.