There have been plenty of reports that Jennifer is getting impatient and threatening to call things off if they don't make it official soon, but now it seems like she might not be the only one ready to pull the plug on Hollywood's slowest-moving relationship.
Sources say that Justin and his Leftovers co-star Liv Tyler have been "racking up a lot of alone time on and off set," and it's reportedly driving Jen crazy.
One insider says the final straw was when Liv began posting photos of herself and Theroux (like the one above) to her Instagram page, and openly talking Justin's "bulge" during promotional interviews.
As you might recall, Jen's had problems with her men falling for their co-stars in the past, so she's said to be particularly wary of the "friendship" between Justin and Liv.
"She went off on Justin and grilled him over the nature of his relationship with Liv," an insider tells Life & Style. "She seems to view Liv as the other woman - and she can't stand her."