Article continues below advertisementOK! can reveal Keith Urban is grappling with regret and jealousy in the wake of his split from Nicole Kidman as the actress is becoming linked to a circle of younger Hollywood men and leaning on longtime industry friends while rebuilding her life.Urban and Kidman, both 58, ended their marriage after nearly two decades together - a decision insiders say has begun to weigh heavily on the country singer.Article continues below advertisementSource: MEGAKeith Urban and Nicole Kidman's marriage unraveled after nearly two decades.