US-based magazine Life & Style quotes an "insider" as revealing that things have been deteriorating between the Twilight stars - who reunited after she had a fling with another man - in recent weeks.
The mole said: "Things with them aren't good. They've been fighting a lot. Rob isn't happy. It's just a matter of time before he ends this.
"Rob is at a point where he sometimes ignores her.
"He'll go out and won't respond to her calls or texts right away. Things will be strained for a while.
"She knows she has to go along with it. She is working hard at the relationship."
But another friend was reported to be a little more optimistic about the outlook for the couple, saying that being apart for work soon will be the acid test.
The pal said: "If they are able to work out being apart while Kristen is filming then they have a shot."
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