It’s everyone’s worst nightmare: There we are on the happiest day our lives…and our true love doesn’t show. Or perhaps it’s just before, with all the flowers and cake set to go. Being left at the altar is a double-whammy: It’s the ultimate heartbreak, but it’s also the ultimate embarrassment in front of family and friends. Who would do this to someone they’re supposed to love, and why? These Redditors reveal the truth behind their “left at the altar” stories. 1. Needs More CowbellMy mom called off a wedding to a man she was engaged to before she met my dad. It was only one week before—and th…