Basically, after building it up for a long time and providing some great forward momentum in their relationship, Batman and Catwoman's marriage is called off because Selina gets cold feet due to what amounts to a 12-year-old's understanding of what makes Bruce tick: She thinks that if she marries him, he'll be too happy to be Batman anymore and leaves Gotham. Despite the fact that Bruce has had several surrogate sons, a biological son, several surrogate daughters, and a ton of friends and allies that have enriched his life over the years and never hindered his ability to fight crime. The entire point of Batman is that he works through his pain and leaves it behind for the sake of others, otherwise he'd never leave the cave. Selina being his wife wouldn't have changed a damn thing about that, but King's an idiot who thinks he's proving a point.
TL;DR: King's an idiot.