Steamy romance between “Dancing with the Stars” hoofers MAKISM CHMERKOVSKIY & PETA MURGATROYD blindsided her former boyfriend and NOW he wants REVENGE.

Damian Whitewood, a pro dancer who appeared on Season 10 of the hit ABC talent show, has been trying to pick up the pieces of his broken heart since learning that he was being two-timed by pretty Peta, an insider revealed.

Damian, 34, and Peta, 26, are both from Australia. They’d been dating for five years and even shared a home together in Los Angeles.

“He thought they had a great relationship,” confided the insider. “Then, all of a sudden, she ran off with Maks.”

When we caught up with him at the Los Angeles airport, Damian told The ENQUIRER that Ukrainian lady-killer Maks had hit on Peta in the past.

“I told him, ‘She’s my girlfriend, buddy! What’s going on?’” Damian recalled. “He didn’t reply. Things had gotten a little distant between Peta and me. And Maks just didn’t stop.”

 Damian’s worst fears were confirmed in May when he heard about Peta and Maks, 32, via Twitter. They immediately started making appearances as boyfriend and girlfriend, a source said. “Damian was crushed. He thought he really had a life going with Peta.”

Despite his heartache, Damian is hoping to use those feelings to his advantage the next time he faces off against his former lover and her new beau.

“This has added fuel to the fire for me,” he said. “I’m going to use the energy from the situation with Maks and Peta to help me perform better.”