Sleazy Eliot Spitzer turned a resort hot tub into a steamy love cauldron over the weekend — kissing and sucking the toes of his topless mistress, Lis Smith, in front of families with children, mortified witnesses told The Post.

The still-married former Love Gov and Smith, Mayor de Blasio’s ex-mouthpiece, were spied frolicking near the family pool at around 4 p.m. Sunday at the Half Moon family resort in Montego Bay, Jamaica.

“It was gross,” said a hotel witness, who was vacationing with her family. “She had her top off.”

The disgraced Spitzer — infamous for wearing his signature black knee socks while having sex with hookers — appears to have a bit of a foot fetish as well, according to onlookers.

“He was licking her toes,” the witness said. “She would sit in his lap. Then he’d put her feet in his mouth. He licked her toes and was playing with her feet.”

He also cuddled and whispered sweet nothings into the ear of Smith — a political flack who lost her chance at being a top spokesperson for de Blasio in part because of her relationship with the raunchy Spitzer.

The couple’s public display became a spectacle at the resort, which was frequented by John and Jackie Kennedy during his presidency.

A 10-year-old boy who saw Smith topless in the pool ran back to his parents and shouted, “Mom there’s an old guy in the Jacuzzi with this girl and she’s topless and she’s got her legs wrapped around him,” sources said.

The boy’s cries — “He’s sucking on her toes!” alerted other guests, who walked over to catch an eyeful.

Spitzer and Smith checked out of the hotel on Sunday night after a five-day trip that started on New Year’s Day.

On Jan. 2, Smith tweeted a cryptic message and picture from the tropical location: “Happy New Year. Here’s to spending 2014 with the person (or ppl) you love.” On Sunday night she followed up with, “I’m at the mercy of the JFK airport gods.”

One passenger on their flight back to New York was disgusted to see the duo.

“Guess who is on our plane? Eliot Spitzer . . . ” Linda Geraghty, @geraghtyvl, tweeted on Sunday night.

“He’s with female companionship,” she later wrote.

Lisa Linden, a spokesperson for Spitzer, denied the account. “These assertions are totally untrue,” she said.

Spitzer and his long-suffering wife, Silda Wall, announced the day before Christmas that they are getting a divorce.