Robert Pattinson: "Why do people cheat?"

(CBS News) Robert Pattinson spoke about cheating just a few months before the world got word that his girlfriend, Kristen Stewart, had done some cheating of her own.

In April, Pattinson appeared in the Italian Vanity Fair and was asked whether he could ever go out with a married woman. "Life is not black and white," Pattinson said. "There are married couples that never see each other. Is that marriage?"

According to Us Weekly, he went on to say, "But there's a thing I've never got: That is, why do people cheat? I can understand the impulse, but not how you can keep two relationships going at the same time for long."

Pattinson, 26, also talked about being serious about relationships. "I'm not the casual-affair kind of guy," he told the magazine. "If I choose to be with someone, it's because I really want it. When I have a relationship, I'm 100 percent into it."

Stewart's confession Wednesday suggests she wasn't always 100 percent herself.

Us Weekly published photos this week showing the 22-year-old actress getting intimate with "Snow White and the Huntsman" director Rupert Sanders, 41. They are seen kissing and hugging inside and outside of a car.

The shots quickly prompted both Stewart, along with Sanders, who's married with two kids, to issue apologies.

"I'm deeply sorry for the hurt and embarrassment I've caused to those close to me and everyone this has affected," Stewart explained. "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."

"I am utterly distraught about the pain I have caused my family," Sanders told People. "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."