Yes, Cuddy absolutely has the right to decide when enough is enough, and she
did say at the beginning that she basically just had to know if it was something that would work or not. So his relapse could have been the moment when she realized it was
not going to work. They had been attracted to each other since they first met in med school and have been dancing around it ever since, so it seemed like she decided she couldn't really move on with someone else until she'd given it a try with House. She totally knew all of his issues and his addiction, but decided to go ahead anyway. But what I don't like about the abrupt nature of both the start and finish of the relationship is that sure, the two events were consistent with each other, but they were inconsistent with the rest of her character. She wasn't particularly impulsive. She was methodical and thoughtful about her decisions. Of course some people are that way with career but are messier with their personal lives, but it still seemed like the writers were sacrificing character development for drama, and I don't like when that happens.
I liked their "normal" moments, too and still a bit salty about how they ended. But 'normal' apparently doesn't do well in the ratings. :/
As for the finale, all I will say is that a) it is
not a delusion (though we do still get some hallucination scenes), and b) it's just a normal episode. I'm conflicted. We'll talk when you get there
Overall, I enjoyed the show very much, even if it did become a bit too formulaic with the cases (it's totally X disease! Nope, it's not. Cue controversial test/diagnoses/breaking and entering. Oh, it's totally disease Y! Nope, not that either. Cue ball tossing/staring at wall/eating lunch with coma guy. Dramatic finish! Puzzle solved! Patient is alive! Or sometimes dead!). But I do feel it overstayed its welcome, and I would have preferred a slow, steady character evolution for him rather than the roller coaster for the sake of gratuitous drama. All of the characters were sort of complex, but they could have been so much more interesting if the writers paid more attention to them.