Robert Pattinson may be an international heartthrob, but it appears that wasn't enough for longtime girlfriend and Twilight co-star Kristen Stewart. The 22-year-old actress was caught in a very compromising position with 41-year-old Rupert Sanders, the director of her latest film, Snow White and the Huntsman. Sanders is a married father of two. What he isn't is Pattinson, the 26-year-old actor Stewart has been with for the last four years. Based on the stunning photos, which show Sanders embracing the actress, it appears there is some serious trouble in paradise. And if there wasn't before, there most certainly is now. According to some insiders, the pics actually look a lot worse than it really is. One insider says that Stewart already realizes the error of her ways: "Kristen is absolutely devastated. It was a mistake and a complete lapse in judgment." The source adds, "She wasn't having an affair with Rupert. It was just a fleeting moment that shouldn't have happened. She never meant to hurt anyone. She's a good person who just made a bad choice." Unfortunately, her poor judgment call was caught on camera for the entire world to see. Just hours before the news broke, Sanders' wife, model and actress Liberty Ross, Tweeted, "Wow." She then followed Us Weekly on Twitter, which ran the telling photo of her hubby and Stewart together. With that, Ross pulled the plug on her Twitter account altogether. Ironically, Ross played Stewart's mother in Snow White and the Huntsman. Late Wednesday, Stewart issued a statement, copping to the affair and apologizing: "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." Sanders also offered his mea culpa to Us shortly afterward: "I am utterly distraught about the pain I have caused my family. My beautiful wife and heavenly children are all I have in this world. I love them with all my heart. I am praying that we can get through this together."