Why Christmas is bad for me

Christmas 2003, I lent an acquaintance a pair of high-heeled shoes for a drag performance that I was unable to do (he was standing in for me).
Christmas 2004 - I learned that he is now dating my ex.
Is there a lesson in this? Is that why my Booba always told me that you never lend anyone shoes or a musical instrument? (I wonder what might have happened had I lent him a musical instrument ...)