Kate and David definitely did make a sweet couple, especially when you saw how great he was with Megan. Some really sweet moments between these two.
As far as Shannen and Julian go, I also think they made a sweet off-screen couple as well. And while I'm not really sure myself why it was they decided to part ways, I do believe if things don't workout with the folks they're with now, there could be a chance for them again in the future.
But well just have to wait and see.