KATIE’s new fiancé JOHN MOLNER is a cheating two-timer as pals fear newsgals is headed toward heartbreak.

KATIE COURIC is on cloud nine as she gets ready to walk down the aisle again, but friends fear the 56-year-old has been blinded by love and is headed for heartbreak!

Incredibly, the former CBS news anchor seems to be ignoring evidence that her future husband, businessman John Molner, is a cheater who was two-timing Katie early in their relationship.

“Katie’s been desperate to find love for a very long time, but unfortunately, she’s not seeing any of the red flags,” a source told The ENQUIRER. “Every one of Katie’s friends told her to hold off and not get married, but it’s like she’s walk­ing around with blinders on.”

Katie – whose first husband, Jay Monahan, died of colon cancer in 1998 – found out AFTER she and John began dating nearly two years ago that he was already involved in a two-year relationship with 28-year-old Jessica Hsu. John and Jessica met while they were both working at Brown Brothers Harriman, the finan­cial firm where he’s head of mergers and acquisitions.

As The ENQUIRER reported in August 2012, Jessica was at John’s apartment, waiting for him to come home, when friends called to tell her that he was at THEIR favorite restaurant with Katie.

When Jessica confronted John about the affair, he promised to end it. But instead, he pulled the plug on their relationship and left all of Jessica’s belongings with the doorman of his building!

“Yes, John cheated on me,” a tearful Jessica told The ENQUIRER at the time.

And that behavior has Katie’s friends concerned.

“Katie is a smart woman, but clearly not when it comes to choos­ing men,” said another pal. “To put it bluntly, she may not have known it at the time, but Katie was basically John’s mistress because he was cheating on Jessica with her.

“That’s why all her friends are so concerned. As the old saying goes …once a cheater, always a cheater.”

Still, the former “Today” host said “yes” to the 50-year-old divorced father during a romantic sunset proposal on the beach in East Hampton, N.Y., over the Labor Day weekend.

Meanwhile, Katie has two daughters, Ellie, 22, and Carrie, 17, from her marriage to Monahan. Although she’s dated several men since Jay’s death, including TV tycoon Tom Werner and jazz musician Chris Botti, it was her five-year romance with Brooks Perlin that really broke her heart, says the friend.

THE ENQUIRER revealed that Brooks – who’s 17 years younger than Katie – repeatedly cheated on her with a younger woman.

“Katie’s had enough heart­ache in her life,” added the source. “It’s no secret that John likes younger women, and Katie’s no spring chicken.

“She would be devastated if he cheated on her.”