KHLOE K makes MOM-AGER flinch after nasty LAMAR birthday snub!

KRIS JENNER’s 58th birthday bash with family at the BevHills Hotel Polo Lounge played like a KARDASHIAN Klan lovefest, but the behind-the-scenes drama got nastier than a segment from their reality show, says an insider!

Despite reports that the family opened their arms to KHLOE’s drug-plagued husband, LAMAR ODOM, Kris initially blew her stack when Khloe announced she’d invited him.

“Kris put her foot down and told Khloe she wanted to celebrate her birthday with family – and Lamar was not part of their family right now,” said my source. “Khloe was furious!

"She couldn’t believe her mother, knowing how desperately she was trying to save her marriage at the time, would exclude her husband from their family celebration.”

Kris refused to relent – until Khloe hit Mom-ager with this ultimatum: “If Lamar can’t come – then neither can I!” (KA-POW, Mommy!)

Finally deciding that having her daughter celebrating her birthday totally trumped all the druggy-drama, Kris reluctantly relented – and actually phoned Lamar personally to invite him!