Justin Bieber: Selena Gomez is 'off limits'

She may have broken his heart, made him cry then told the whole world about it on late night television, but when it comes to ex Selena Gomez, Justin Bieber refuses to go negative.

[Selena's] been bashing him but Justin has ordered everyone around him not to fight back, a source toldRadarOnline. He told his friends and everyone else about Selena, shes off limits,

He told everyone to leave her alone.

The 19-year-old Canadian heartthrob and 20-year-old Spring Breakers star were together for two PDA-filled years before breaking up around New Years Eve while vacationing in Mexico.

In the resulting months, Bieber has been in a bit of a tailspin:allegedlysmokingmarijuana,consistentlywalking around topless, showing up late for and even passing outat his concerts.

Meanwhile, Gomez, who has been doing the promotionalcircuit for herrisque new film, Spring Breakers, has been anything but shy about their relationship, publicly telling David Letterman that she made the Baby singer cry.

Now, the last time he was on, he and I got into a conversation and he said something and I said something, and then he said something and I said something, and I made him cry, Letterman explained to Gomez, who quickly fired back,Well then, that makes two of us.

[Justin]doesntwant to fuel the fire and he justdoesntwant it to be that way with her, the source explained. I dont want anyone saying anything negative about her, is what he told his pals.