Amber Portwood and Clinton Yunker have broken up, paving the way for her eventual reconciliation with baby daddy/punching bag Gary Shirley.

Just kidding ... about the second part.

The controversial Teen Mom star ended the "mature relationship" this week, and the mixed martial artist has wasted little time moving on.

PORKER: They seemed like such a good match, too ...

"I was out with some friends at Buffalo Wild Wings and recognized Amber's boyfriend Clinton, but he was all over some girl," a source said.

"He told me Amber broke up with him."

In true reality TV style, things got crazy when Gary Shirley, who's been criticized for egging Amber on, showed up to the same restaurant.

"Clinton's brother was there with him and he tried to pick a fight with Gary and friends," the source said, though no punches were thrown.

Police were called to the restaurant but no one was arrested.

Amber Portwood and Gary Shirley had planned a trip to New York City to celebrate New Year's Eve and the prospect of getting back together.

Those plans were nixed when a No Contact Order was given to Portwood in lieu of her domestic violence charges from the local D.A.'s office.

She pleaded not guilty, but the No Contact Order remains.

That order bars her from seeing or having any contact with Shirley. It remains to be seen if it will be lifted. As far as Clinton Yunker goes?

"Clinton didn't seem too torn up about the breakup," the source said. "In fact, he seemed ecstatic and was really having a good night!"