"I get it. I screwed up. The whole Ruby thing." Would you like some salt to rub into those gaping wounds, Dean? Maybe some alcohol too? "I was an idiot. But you were in Hell and I had no one." Well, aside from Bobby, if Sam had only bothered to call him...
"Ruby was there when I needed someone." Okay, so maybe she was using him as a giant moose-sized puppet, but it felt like she was the only person in the world he could rely on. Hindsight was 20/20, right?
"I had to jump into the Cage, Dean. What else was I supposed to do?! There was no other way. Anyway! You're the one that went around poking and prodding at my soul and getting it shoved back in me all broken!"