Jennifer Aniston's 'Relationship in Crisis'! Is Justin Theroux Cheating with Ex Heidi Bivens?

Jennifer Aniston first hooked up with her current boyfriend, Justin Theroux, while he was still involved with his girlfriend of 14 years, costume designer Heidi Bivens. And now Heidi might be homewrecking Jennifer right back.

According to The National Enquirer, the Emmy winner "unleashed her fury" and called Justin a cheater when she discovered that he has been "calling, texting and e-mailing Heidi without Jen's knowledge" for months. It looks like Jennifer and Justin won't be having a baby anytime soon!

"In Jennifer's book, what Justin did was cheating -- he was going behind her back to maintain ties with his ex," a "close source" dishes to the mag. "She was furious and read him the riot act, plunging their relationship into crisis."

Really? "Calling, texting and e-mailing" someone now equals cheating? Sure, the "without Jen's knowledge" part is shady. But Justin and Heidi were in a relationship for 14 years and probably still have a lot of ties to each other, so it's likely they have legitimate reasons to stay in contact. Jennifer should be encouraged that her boyfriend and his ex can be civil to each other and handle their split like grown-ups. But although Jennifer's rep denies she and Justin are having problems, the Friends star "exploded" when she discovered the secret communication.

"They stayed in touch very sporadically at first, but now they're talking all the time," "another insider" tells The Enquirer of Justin and Heidi. "He'll e-mail, text or call -- when Jen's not around, of course -- and they talk about everything. He asks Heidi's advice about his career and even discusses his love life with her [writer's note: well, he definitely shouldn't be doing that, for multiple reasons]. For Jen, it's the ultimate betrayal. Justin has a lot of explaining to do to regain her trust, and it may be too late already."

If Justin and Heidi are back in contact, hopefully he's not keeping her hanging on so he can have a fall-back option when his relationship with Jennifer goes south. But hopefully Heidi would know better than to go back to him anyway. Heidi was reportedly blindsided by their split and incredibly upset when he hooked up with Jennifer, so hopefully she wouldn't go running back to the guy who was seemingly so eager to throw away a 14-year relationship. She definitely deserves better than that! But if Jennifer and Justin do break up over this, there will no doubt be an onslaught of "Jennifer gets cheated on again!" stories in the press.

What do you think? Is Justin Theroux cheating on Jennifer Aniston with Heidi Bivens? Is Jennifer making a mountain out of a molehill? Sound off in the comments!