Kris Jenner -- 'Boyfriend' Bragging About Wild Sex is a Fake!

Kris Jenner has another imposter on her hands ... this time a guy claiming to be the man she's banging.

Kris is dating a guy named Corey Gamble, so when another website snagged an interview with a dude claiming to be Corey they were all ears.

The guy then spilled some pretty juicy details about his relationship with Kris ... saying they were having great sex. He also says he's a kept man, because she gladly pays for everything. And to make things even more interesting ... he says Kylie is living with Tyga.

Here's the thing. We found out the guy is NOT Corey ... he's a phony who talks a good game. One clue ... in the interview the guy says he hasn't spoken with his mom about the relationship but thinks she'd disapprove. Corey's mom is dead.

As for the real deal ... as we reported Kris and Corey -- who works as one of Justin Bieber's road managers -- are indeed dating. We're told Kris is telling people it hasn't gotten physical.

They're definitely spending a lot of time together. The photo was taken as they left a Malibu sushi joint Monday night.