Who does Damon end up with in the books series ? Elena or Bonnie ???

I have read the books so far too, and hes wanting elena, mainly cause of the katherine look alike fact and cause stefan has her now. buuuuut he has an attraction to bonnie, it says in the books that he has a connection with her and calls her his girl, along with elena and doesnt want anything to happen to either of them, hes not too fond of meridith in the books tho. lol