Back in April 2004, longtime loves Mario Lopez and model/actress Ali Landry tied the knot — only to annul the union two weeks later, amid rumors of Lopez’s rampant cheating.

Now, almost seven years later, Lopez fessed up to at least one major indiscretion that took place during a wild bachelor party weekend in Mexico.

Lopez, 37, spilled the beans to Howard Stern on his Sirius XM radio show on Thursday. “It was my bachelor party,” the “Extra” host admitted, explaining that he had been “bouncing around” Mexico with his cousins. “I had no business of being in that position,” he said, offering that he “messed around” with another woman.

He elaborated a bit on the fling. “It was spring break … everybody was hanging out. That was a situation where I was not mature and man enough.

Also On RadioNOW 100.9: