Stewart's romance with her Twilight co-star Pattinson came under scrutiny this week (begs23Jul12) after photos obtained by Us Weekly magazine appeared to show the actress kissing her married Snow White and the Huntsman director Sanders earlier this month (Jul12).
She broke her silence about affair rumours on Wednesday (25Jul12), apologising to Pattinson for her behaviour in a statement which read: "I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected. This momentary indiscretion has jeopardized the most important thing in my life, the person I love and respect the most, Rob. I love him, I love him, I'm so sorry."
The British hunk has allegedly been left heartbroken by the admission, and a source close to the couple tells People.com Pattinson has now packed his bags and left the property they called home.
The insider adds, "Kristen really loves Rob more than anything. He's all that matters to her right now... (but) I'm not sure they'll be able to recover from this."
Meanwhile, Sanders' father Michael is confident the director and his model/actress wife Liberty Ross will work through their troubles because the media storm has been "a lot of fuss about nothing".
Michael Sanders tells People.com, "He is very honourable, hardworking and (a) dedicated father and filmmaker... Of course their relationship will survive this. This is nothing - they will definitely survive all of this. It is all a lot of fuss about nothing."
Rupert Sanders also issued a statement about the affair allegations on Wednesday, admitting he is "utterly distraught" about hurting Ross, who played Stewart's mother in the Snow White film, and their young two children.