Sources close to the situation tell TMZ ... Kim quietly stopped following Larsa on Instagram at the end of last year when she made a decision to unfollow EVERYONE, and bring her following count down to zero.

We're told Kim felt she needed a fresh start, social media-wise, and wanted to start over by following only accounts of her family and childhood friends -- all to reduce her feed, and keep a clear headspace.

Most folks thought Kim and Larsa were still super close -- until they noticed this week they weren't following each other anymore -- but our sources say the ladies' friendship simply grew apart over time because life got in the way.

We're told there was no drama between Kim and Larsa -- and the rumors floating around LP messed around with Kanye West or Tristan Thompson are not true.

Our sources say Kim is focused on getting Kanye healthy, her 4 young kids, law school and juggling her 3 business. Larsa, meanwhile, says she's focused on her kids, her new fitness line and her "relationships in real life."

Our sources say Kim and Larsa are just in a different place in their lives, and while they're not as close as they used to be, they have no ill will and still stay in touch. Case in point ... we're told Larsa recently visited Kim in Los Angeles.