GEORGE HAMILTON was left red-faced with embarrassment when his former fiancée waltzed down the aisle with another man!

The 74-year-old TV personality and former ladies’ man was left to lick his wounds as gorgeous “der­matologist to the stars” Dr. Barbara Sturm, 40, tied the knot with Hol­lywood consultant Adam Waldman at Cher’s palatial Malibu beach house on Sept. 7.

“George and Barbara had been together for four years, and he had every intention of settling down with her,” said a source

“They were talking marriage and even starting another family.”

George already has grown son Ashley from his marriage to Alana Stewart, and 13-year-old love child George Thomas, from his relationship with former model Kimberly Blackford.

As The ENQUIRER reported last August, Hamilton confessed that he’d finally given up his playboy ways because it was too tiring.

“I honestly don’t cheat any­more,” he told an interviewer. “First of all, it’s difficult to remem­ber all those lies. Second of all, the last thing I want is to have my woman leave me now.”

But in the end, George had little say in the matter. The source reveals that Barbara got tired of being alone while he spent time on the road playing Georges in a touring production of “La Cage Aux Folles.”

“When Barbara met Adam, they fell deeply in love,” added the source. “And that was THAT.”