Among the Ruins (1959)

This run-of-the-mill romantic comedy-drama is set in a university in Cairo and begins with a professor and a young student about to be married. Just at that point, their wedding is interrupted by the rest of the movie, which happens to be an extended flashback. At issue is whether the couple can actually marry or not because unless a few big questions can be answered in the negative, they are actually brother and sister. So the story segues into the love life of a gifted writer as he is caught between his desire for a beautiful young woman and his feelings for his wheelchair-bound wife.