By Jennifer Garcia
May 17, 2010 12:00 PM

Their son Jaden’s 8th birthday is two days away, on May 1, and David Boreanaz and Jaime Bergman would give anything to simply be worrying about finding him the perfect gift. Instead, the Bones actor and his wife of nearly nine years are grappling with something deeply painful-news that they have finally decided to reveal publicly. “I haven’t been faithful to my wife,” the actor admits to PEOPLE. “Our marriage has been tainted with my infidelities. I was irresponsible.”

An admittedly “nervous” Boreanaz settled into a couch at the Hollywood Hills home he shares with wife Jaime, who took a seat in a chair beside him. “It’s very difficult for Jaime and me to come forward,” says the actor, his eyes welling up with tears. The pair-who married in 2001 and have two children, Jaden, 8, and Bella, 8 months-have struggled privately for the past year after Boreanaz admitted his infidelities. But last month Boreanaz, 41, says he was faced with “some sort of extortion attempt,” which prompted them to go public with their fight to save their marriage.

“I was associated with a woman who I was involved with and had a relationship with. She asked for money,” admits Boreanaz, who declines to name her or any of the women he has been involved with (past tabloid stories have linked him with Rachel Uchitel, Tiger Woods’ reported mistress). “I felt as though I was being blackmailed or there was some sort of extortion.” The woman, he continues, “was asking for six figures and would go to the media if we didn’t pay. I felt threatened.” Adds Bergman, sternly: “She believes David loved her, and she’s claiming she didn’t know there were other mistresses involved. She feels entitled to something… . It’s not going to work with us.”

Unlike other celebrities who have recently admitted to cheating on their spouses-including Tiger Woods, David Letterman and Jesse James-Boreanaz is making this revelation with his wife at his side. And while the couple had little physical interaction during their interview with PEOPLE, they made it clear they’re doing all they can to salvage their relationship. “There’s anger. There’s hurt. There’s disgust. But there is a love,” says Bergman, 34. “For me to walk away from that, I don’t think would be the right thing to do.”

While TV heartthrob Boreanaz seemed like the perfect catch (long before Robert Pattinson, he made women swoon as the vampire Angel on Buffy the Vampire Slayer and its spinoff series Angel; he now plays an FBI agent on the hit FOX forensics drama Bones), the couple’s life at home was far from picture-perfect. “We lived completely separate lives,” says Bergman, an actress. While she spent time between L.A. and their Utah home, renovating and caring for their kids, Boreanaz spent long days on the Bones set and traveling for work. “He would come home and I would be surfing the web and he would flip on his laptop,” she recalls. “There was no connection, no ‘How was your day?’ As much as David should have never gone outside the marriage, there was neglect on my part. It took a crisis; it took infidelity to get us off our asses and work for what we want.”

Last year “David came forward and told me on his own [about the cheating],” says Bergman. What prompted the revelation? “It eats you up,” says Boreanaz. “I found myself hurting on the inside but trying to cover up on the outside, and it was a lie. I was living a lie.” The actor says his actions were caused by “narcissism and arrogance. There was a lot of selfishness.”

Once Boreanaz came clean about his infidelities, “my first reaction was, ‘I’m leaving David,'” says Bergman. “How could he do this to me, our children, our family? I was totally shocked.” But realizing that “if there’s an ounce of love, we need to work on it for us,” she agreed to try to repair their relationship. Through therapy (Boreanaz has biweekly individual sessions in addition to their couples’ therapy), the pair have been working on moving forward with all secrets finally out in the open. “We’re working on our marriage,” says Boreanaz, “and repairing what has been damaged so badly.”

But can their marriage be saved? The two say they are hopeful-but realistic. “I’m not saying everything’s okay,” admits Bergman. “It’s going to be a long, bumpy road.” Agrees Boreanaz: “We’re putting the pieces back together, [maybe] in a better way. And that’s what I’m committed to.”