Couples counselors see this scenario all the time: A couple comes to them say 18, 19 times. First few months there is a lot of old garbage hauled out. That old girlfriend that keeps calling. The line of credit she opened without telling him. And would it kill you to pick your gym clothes up off the bathroom floor?

But at some point the old barbs don’t work anymore. One party decides that he or she is done and the tried and true insults just don’t get the same reaction that they used to.

So it seemed to me watching last night’s Democratic debate. It was for the most part an amicable affair; if as reported Clinton’s camp had been warring over how hard to come at Obama, the nicer side seemed to have won — most of the time. And when the non-issue of Obama plagiarizing words from a supporter’s speech came up, and Hillary tried to hit him with a late, lame shot (calling it “change you can Xerox”), the crowd groaned and her opponent shook his head. He didn’t care anymore. He was so over her.

And small wonder, given estimates that HRC must win very decisively (ie, by more than 10%) in TX and OH to stay in the hunt. The nomination is now his to lose. And though her closing remarks were truly altruistic and brought the crowd to its feet, some such as Chris Matthews saw them as valedictory, like the scene where the hero does something really noble because he knows he’s not coming back. (For those who missed it, most of the questions posed to the candidates had been substantive ones regarding health care, immigration, the state of the economy and other hot-button issues. But the last, from CNN moderator Campbell Brown was a big meatball of a slow pitch: “I’m wondering if both of you will describe what was the moment that tested you the most, that moment of crisis.” (She did not get to ask them if they were a color, what color they would be.)

Obama actually fumbled this one, offering a precis of his life (single mom, absent dad, bad choices, call to service) that sounded more like a Hollywood pitch than a defining-moment moment. Hillary romped, first going for self-pity and sympathy — “Well, I think everybody here knows I’ve lived through some crises and some challenging moments in my life” (huge applause) — before putting some serious spin on it by recalling watching limbless Iraqi war veterans limping their way into a hospital in San Antonio. “You know,” she concluded, ” the hits I’ve taken in life are nothing compared to what goes on every single day in the lives of people across our country.”

She knocked it out of the park, proving if nothing else that the old girl still has some serious game. Obama did not look too concerned, though. In his mind I think he may already be out the door, looking at apartments. Perhaps he’ll ask her to join him as partners — strictly business, of course — when this messiness is over. She did, after all, take his hand in front of everybody and say, “Whatever happens, we’re going to be fine.”

Isn’t it great when therapy works? Makes up for those other clients who are in so much denial.