By Michelle Tauber Alexis Chiu Oliver Jones
April 12, 2010 12:00 PM

For much of the past two weeks, Sandra Bullock‘s husband, Jesse James, did his best to stick to his routine: dropping off his three kids at school, grimly showing up for work at West Coast Choppers in Long Beach, Calif., roaring off on a souped-up motorcycle whenever he needed time alone. But in the wake of the drama that exploded on March 15, when Bullock learned of the cheating scandal that has sent their nearly five-year marriage into a tailspin, James is now seeking help “at a treatment facility to deal with personal issues,” his rep told PEOPLE in an exclusive statement on March 30. (The rep did not specify what kind of treatment he had entered.) “He realized that this time was crucial to help himself, help his family and help save his marriage.” Meanwhile, Bullock has chosen to stay behind closed doors and cope with the shattering news in private. The actress is still “in shock,” says a friend of the couple’s. But as she’s had more time to think, “She’s sad-but getting angrier.”

In the days since Bullock’s “life as she knew it changed,” as a friend put it, new revelations have continued to strike her once seemingly blissful marriage. Four women have now emerged claiming to have had affairs with the West Coast Choppers CEO, 40 (see box). James-who a source says entered treatment on his own and not as a result of any ultimatum from Bullock-“let things go too far and didn’t realize how it would affect Sandy and the kids until it was way too late,” says a friend. Adds another: “He loves Sandra.” To win her back, “he would do anything.”

It may be too late. Bullock, 45-who moved out of the home she shared with James the day she learned of his infidelity-is wrestling with what to do next: launch a divorce or give James a chance to mend the damage. Crucial to her decision is how any step will affect her relationship with James’ kids from his two previous unions: Chandler, 15, Jesse Jr., 12, and Sunny, 6. “They were absolutely like her kids,” says a source who knows the couple. (Despite reports that Bullock might petition to adopt Sunny, she has never planned to adopt any of Jesse’s children, her rep said in a statement.) The kids are a top priority for James too. “He has been immersing himself in his children and trying to keep them from crying too much because they miss Sandra,” says one of his friends. “The only way he got through this week was a lot of kisses from those kids.”

And yet as claims of more affairs surface, the motorcycle mogul’s public image has taken even more of a beating. Several sources tell PEOPLE that James had a reputation as a womanizer since his earlier marriages. “He’s a huge flirt,” says a woman who says she hooked up with James before his 2002 to 2004 marriage to ex-porn star Janine Lindemulder. “He was with Janine when I met him, and I could see his neck craning to see me. He definitely notices pretty girls.” A former employee of James’ says that when it comes to women, “I don’t think he can help himself. He’s the kind of guy who, if you give him enough rope, he’ll hang himself.” Still, a current female employee says she never witnessed him behaving inappropriately. “Jesse is a big dude and he [can look] very intimidating, but he’s very sweet. Hearing all this stuff about him is just sad,” says a staffer at West Coast Choppers and his restaurant Cisco Burger.

After marrying Bullock in July ’05, James told PEOPLE, “I’m older and smarter. The same work ethic I’ve applied to every other aspect of my life, now I’m applying it to my marriage.” But several of the alleged mistresses say James acted the part of a single man. “He never mentioned his wife,” says Brigitte Daguerre, 43, who says she struck up a friendship with James in ’08 that became something more and ended shortly after. Says Daguerre: “If I had known, things would have been very different. I made a mistake.”

Many who know Bullock-a woman who one friend describes as having “a great bull—- meter”-are puzzling over how she was so deceived. “They’re in a celebrity marriage where you really have to trust each other, because the opportunities to stray are huge,” explains the friend of the couple’s. “He was a champ around her. He would make her feel like a million bucks….She bought into their life that she created, with his kids, and Jesse played the role.” James’ friend says he may have fooled himself as well. “It was almost like he couldn’t believe what was happening to him-that he fell in love with Sandra Bullock. And bottom line: He is who he is. He’s learned from things, but he will always be the same rough-around-the-edges guy.”

Yet as a father, James often revealed his inner softie. “He’s a great dad,” says a longtime employee. “He loves his kids more than anyone can ever know.” Given Bullock’s tight bonds with his children, “this is crushing for them,” says James’ friend. “Jesse definitely feels a lot of guilt over that-like he failed as a dad.”

Now all eyes are on Bullock as she struggles with where to go from here. “Jesse had the best thing that ever happened to him, and he tore it apart,” says a James pal. “Sandy didn’t deserve it, and he knows that.”