Yeah, we don't know. IF that's the thing he was talking about that was the "generation changing" event, they may not let him do it, OR they may be letting him do it but they just didn't want 15 issues of a BatCat relationship story taking up the main Batman line, so they gave him a separate book for it. It could be that they want to go back to more typical Batman stories in the main line, and he wants to do some big relationship driven coda to his arc and they didn't want it to take place there (or Harras doesn't, since he doesn't like King's style apparently).
The Batman/Catwoman book is 100% canon apparently, so marriage could still happen. A wedding may even spin the book off, who knows.