I agree, Cho was Cedric's. I knew Harry and Cho's relationship would be dysfunctional because Cho was obviously still grieving Cedric's death. I didn't hate Cho, I felt really bad for her; her boyfriend had died and she was obviously still in a great deal of pain. I always thought it was really stupid that Cho starting dating Harry though, she was obviously wasn't ready for another relationship yet and it was just going to end in pain and heart-break for both of them. Harry and Cho's relationship may have turned out better if Cho hadn't still been grieving Cedric's death but I think it worked out for the best. Harry belongs to Ginny, not Cho; poor Ginny had a crush on Harry for 6 years (even when she was dating other guys I don't think she even got over her crush for Harry) and Harry was running around chasing Cho.