On Sunday, Naveen Selvadurai, co-founder of the social networking site Foursquare, announced that he was leaving the company by the end of March. “[Fellow co-founder] Dennis [Cowley] and I have been discussing timing for a while, and decided that now, on this anniversary, it feels right to begin the transition,” he wrote on his personal blog.

Three years ago, Crowley and Selvadurai launched Foursquare at SXSW 2009, and over the course of the last few years, the company has grown from about one hundred beta testers to a community of over fifteen million users.

So why would Selvadurai want to leave the company now? On his blog he wrote that “after three years, I feel I’ve done all I can do and I’m moving on.”

His announcement made it sound like he chose to leave the compnay, but that may not be the case.

An unnamed source told Business Insider that Selvadurai is being pushed out of the company by Crowley and the Foursquare board of directors. The source also said that Selvadurai was “financially ‘screwed’ when he was forced out.”

Why would Foursquare want to push Selvadurai out? A source for Business Insider said that Selvadurai and Crowley “hadn’t been getting along” and another source says that Selvadurai has been feeling lost and frustrated by his role at Foursquare.

While details of the Selvadurai’s departure are still a bit hazy, start up seperations are nothing new. Thanks to the film The Social Network, everyone should be familiar with the Eduardo Saverin, co-founder of Facebook who was forced out of the company by Mark Zuckerburg. Even Steve Jobs was fired from from Apple, only to return a few years later.