Katie Couric has been dumped by sitcom king Tom Werner, her on/off beau for more than four years.

Werner told friends Katie’s constant complaining about the Today show was becoming too much to handle.

A friend of Katie and Werner told The National Enquirer: “Tom loved Katie but he just couldn’t deal with her moaning. It ultimately killed the relationship. She should’ve learned not to take her stress home with her.”

Katie is struggling with Today‘s dwindling ratings and competition with co-host Matt Lauer for more compensation. She wants a raise in her annual $15 million salary when her contract ends next year and is going for $100 million over five years.

Just days after the split, we spotted Katie, 48, cutting a lonely figure on June 25 as she strolled the streets alone while on vacation in Paris.

Werner, worth $600 million as co-owner of the Boston Red Sox and a TV production company, first began dating Katie after filing for divorce from Jill, his wife of 28 years, in October 2000. But Katie called it quits on the relationship with Werner, 55, last November. She was upset Werner had failed to set a wedding date when his divorce went through.

In the months that followed, Katie dated jazz musician Chris Botti and artist Stephen Hannock. But friends saw the new romances as ruses to make Werner jealous and come back to her. The plan seemed to work as Katie and Werner were back together in March. But it seems Katie’s job woes have finally sounded the death-knell of the relationship.

The friend added: “It’s a shame — we were hoping they would get married. They’ve been on and off a few times but this time is different — Tom says it’s for good.”