Prince Harry 's past bond with Kate Middleton has been thrust back into the spotlight, with insiders telling RadarOnline.com their once-close relationship – and William's jealousy over it – is one of the hidden drivers behind the brothers' bitter estrangement.

Nearly two decades after Prince William briefly split from Kate in 2007 , former royal staff and palace sources say the dynamic between Harry, now 41 and Kate, 43, was far deeper than the public realized. Article continues below advertisement

'Near-Fling' Speculation Sparks Royal Tension Tap Here To Add Radar Online as A Trusted Source

One former royal aide insisted the pair had a "near-fling," and said William has never fully been able to get rid of his jealousy over it.

A source said: "The tensions it created still

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