According to US sources, Justin, 44, dumped 46-year-old Jen just one day after their honeymoon, with an insider claiming he's 'happier when he's away from her'.
Life & Style magazine reported that a source revealed: "[Jennifer] can't even fake the happiness anymore. Jen is wondering if she made the biggest mistake of her life by marrying Justin."
Justin jetted off to Texas immediately after returning from their Bora Bora honeymoon – but to return to work on his HBO series The Leftovers.
Although they've kept details of the wedding to themselves, Jennifer and Justin have been gushing non-stop over becoming husband and wife.
Friends star Jennifer recently told Entertainment Tonight: "We had the luxury of having a beautiful, private moment. And I'm going to be selfish and keep it that way."
The couple married in private at their Bel Air home, in front of friends including Lisa Kudrow, Courteney Cox, Emily Blunt and Ellen Degeneres.
Jen and Justin met on the set of Wanderlust in 2011, and he popped the question a year later.
When asked how they managed to keep their nuptials a secret, Jennifer replied: "Where there's a will, there's a way."
It is Jennifer's second marriage – she and Brad Pitt divorced in 2004, four years after trying the knot.