Earlier this summer, Snow White and the Huntsman director Sanders was pictured in an embrace with Twilight actress Kristen Stewart.
Ross initially left Sanders, but recently is said to have reconciled with him and the pair are said to be going to marriage counselling to repair their relationship.
A source told The Sun: "It was Rupert's suggestion that he go to therapy with Liberty.
"He will do anything to save his marriage because he loves his wife and knows he screwed up. They have been married since 2003, and have two children together. They have a life together.
"Rupert and Liberty have been going to the therapist for weeks. Time will tell if it works, but Rupert is hopeful it will save the relationship."
> Robert Pattinson 'accepted Kristen Stewart didn't sleep with Sanders'
> Robert Pattinson friends 'want him to move on from Kristen Stewart'