Blake's Heartbreak! Gwen Still In Love With Ex Gavin Rossdale: 'He's Her One & Only'

Gwen Stefani is harboring a shocking secret, RadarOnline.com exclusively learned — friends say she's still in love with her cheating ex Gavin Rossdale!

The No Doubt singer — who has been in a public fairy-tale romance with country hitmaker Blake Shelton — made the staggering confession to pals last month after she and former hubby Gavin coldly ignored each other during a grueling 14-hour mediation session over how to raise their three children!

"She can't stand Gavin because she thinks he's a cheater and a bad dad,"said a source. "But she STILL insists on calling him the love of her life!"

The couple's 13-year marriage blew up in 2015 after Gavin's sordid affair with the family nanny — and the bickering exes have been at odds ever since.

Now, 48-year-old Gwen has accused the British rocker of not seeing their sons — Kingston, 12, Zuma, 10, and Apollo, 4 — for five full weeks this summer!

"Gwen sees no end to his selfish behavior!" the insider continued.

"She told the mediator he isn't pulling his weight!"

Sources told RadarOnline.com exclusively that even after three years of dating 42-year-old Blake, Gwen has labeled the country singer a "rebound romance" — and even considered walking away from the relationship!

"If they don't have a kid soon, she's said they won't ever get married!" sources dished.