By Ulrica Wihlborg
April 09, 2012 12:00 PM

Her picturesque six-acre Santa Ynez Valley, Calif., farm is the very definition of tranquility, but as Jennie Garth curls up in an Adirondack chair, she seems anything but serene. “I’ve never been this stressed in my life,” says the Beverly Hills, 90210 actress. “I’ve felt stress in the last couple of days like none before.” It’s no wonder: On March 13 she and her husband, Peter Facinelli, 38, announced that their marriage was ending. The ensuing flurry of headlines have pushed Garth to the brink. “I’m suffering from anxiety now,” says the actress, seeming emotionally exhausted. “It feels like an elephant is sitting on your chest.”

Yet at times Garth can still summon the upbeat attitude that made her a prime-time dream girl on 90210, then a sitcom sweetheart on What I Like About You and then a fan favorite on Dancing with the Stars. Still blonde and adorable, she tries mightily to remain positive as she discusses life on the ranch with the couple’s three kids, Luca, 14, Lola, 9 and Fiona, 5. “I’m not scared,” she begins. “I have an amazing family in my girls, and in Peter.” But then she realizes she’s just spoken of her marriage as though it were still intact. “That’s the fighter in me,” she says, her voice beginning to waver. “I don’t think I’ll ever give up.” She pauses as she realizes, after 11 years of marriage and 16 years together, what she’s faced with letting go. “On him,” she clarifies. “I don’t think I’ll ever give up on him.” With that, her resolve crumbles, and Garth’s eyes well up.

While their marriage had been slowly dissolving over the past year, Garth was still left reeling by the decision to split, which she says Facinelli initiated. “You get the rug pulled from under you. I have no landscape of what my future will look like, where before I had something that I could count on,” she says. In the dark months afterward, she says, “I would take the girls to school, then go back and get into bed and not get up again until it was time to pick them up from school, and I had to pretend everything was fine.”

But it wasn’t. “We both saw it unravel and it was painful,” she says. “I tried everything I could to save our marriage.” Instead, over several months this past fall, Facinelli made it clear to his wife that he wanted a divorce. (Facinelli declined to comment to PEOPLE.) “I was very resistant,” Garth says. “I didn’t want it to happen.” The shock of her husband leaving her still feels raw. “He did what he needed to do. I don’t want to talk for him,” she says, “Or do I? Of course I wish he had wanted to try harder, try again, try something else.”

Early on during their troubles, with Facinelli shuttling between Vancouver, where he was filming the Twilight movies, and New York City, where he shoots his hit Showtime drama Nurse Jackie, Garth decided to relocate their family from their Los Angeles-area home to their ranch. “He was gone anyway,” Garth recalls of the 2010 move. “And I felt I needed to be in a safer place for what was coming. I must have had some intuition about it.” Still, with Facinelli committed to flying home whenever he had even a single day off, Garth had faith their rift was merely a low point in their relationship. “I was hoping,” she says, “we would get through this.”

It wasn’t an unlikely wish, considering the obstacles they had already worked through. A self-described “country girl” from Illinois and a New York City-raised actor, the couple met in 1995 on the set of the TV movie An Unfinished Affair. “We were just crazy about each other,” says Garth. Nine months later, Garth discovered she was pregnant with their first child, Luca. Yet the couple didn’t wed for another five years, in 2001. “I wanted him to want to get married,” says Garth, who converted to Catholicism for her husband. “He didn’t want to get married until then, and I was fine with that.” (Garth now says she’s no longer a Catholic but is spiritual.)

As their family grew-they sweetly referred to themselves as the Facinelli Five-“people looked at us as an example of how they could also stay together,” says Garth. But in reality, their relationship was not always as rosy at it seemed: “There were the common issues any woman has, and especially a woman in this industry of insecurities,” Garth says of some conflicts. “There was jealousy over having to see your husband onscreen with another woman. It wasn’t always easy. It wasn’t always fun. But we worked through it.” The couple attended therapy “several times” over the years, she says. “It helped us.”

As her husband’s career took off, Garth says she was happy to embrace the stay-at-home-mom role. Facinelli’s success from Twilight provided a reversal from their earlier years together, when Garth had been the more famous of the two. “I was so excited for that shift. I was so excited to be on his arm,” she says. “It was something I’d wanted for him for a long time.” But the effects of his fame had their downside. “Maybe he’s just hitting his stride as an actor and that’s interesting to him,” she says cautiously. “He deserves to do with that success whatever he wants to do with it. I look at the industry differently [than him]. I don’t look at it like you have to strike it while it’s hot. I’m not sure what it is that he’s looking for right now. I don’t even know if he knows. Did he change? You’d have to ask him. We want different things now.” As for the Internet reports that Facinelli has been unfaithful? “I believe those rumors are completely false,” she says adamantly.

Even after Facinelli called it quits, the pair kept up a painful charade for months. “It was never the right time,” says Garth. “There were birthday celebrations and Christmas and we always thought, ‘Let’s keep it together for the kids.'”

But ultimately they had to tell their children the truth. Together with their therapist, Garth and Facinelli-who plan to share custody—sat down with their daughters and told them they were getting a divorce. “That was the second worst day of my life,” says Garth (the worst: her father’s death in 2008). Unable to break the news herself, she let Facinelli and the therapist tell the girls: “I just held them. They cried. I cried. It was really hard.”

Since then, Garth and her daughters have tried to create a life of normalcy together that includes playdates, soccer games and taking care of their animals. She has also kept busy filming her CMT network reality show, Jennie Garth: A Little Bit Country, premiering April 20, which follows their life on the ranch. All this as she prepares to turn 40 on April 3. ” I’ve lost my footing a little bit,” she says about the big day. “It’s not scary, but it doesn’t feel awesome.”

With her dealings with Facinelli now sometimes difficult and emotional-“It’s complicated,” she explains-Garth isn’t ready to contemplate falling in love again. “I can’t imagine being with anyone else,” she says. Nor can she fathom the idea of someday seeing her soon-to-be-ex with another woman. “That will hurt,” she says. “But I have to let it go.”

Still, the actress insists that she’s going to be fine. “I can’t change it. I can’t be sad and stay in bed about it anymore. I have to move forward,” she says. She’s begun removing her wedding photos from the hundreds of framed photographs on display in her home; her wedding ring has already been taken off. “I’m slowly finding my own voice again,” she says. “There are days when it seems I got it all figured out and days when I lose sight. I just have to keep on my path.”