As the 37-year-old E! host chooses a double mastectomy, Giuliana Rancic and husband Bill Rancic open up to PEOPLE in this week's issue about continuing IVF and finding hope after heartbreak. The reality star thought she had beat cancer easily – only to be faced with a devastating diagnosis. Now Giuliana and Bill talk about the battle ahead.

After days spent grinning through celebrity interviews on the red carpet, playfully bantering with colleague Ryan Seacrest and dissecting stars' fashion choices, Giuliana Rancic was getting ready for bed in Los Angeles when reality finally hit. In less than two weeks she would be losing both her breasts in a double mastectomy. "I started crying, and Bill pulled me into bed and was holding me," she says of her husband of four years. "I didn't think the surgery was really ever going to come." Nor could she absorb the hard truth that the breast cancer she'd been diagnosed with almost three months earlier had not vanished, despite a double lumpectomy performed just two months ago. "I thought it was going to disappear," Giuliana admits. "It was embarrassing to say out loud, because what fool would think it would disappear? But I kept saying it in my head and crying." After breaking down that night, she summoned her resolve. "I said to Bill," she recalls, "I'm really ready to do this."

Now, as she heads into what she plainly calls "the fight of my life" in the wake of her shocking cancer diagnosis, Giuliana is steeling herself to undergo a bilateral mastectomy, followed by reconstructive surgery on Dec. 13. Facing the radical procedure, "am I scared? Absolutely," confesses the TV personality, who arrived at her decision after learning that cancer in her right breast remained. (The disease was "in the early stages and had not spread," says Bill.) The operation caps a hugely challenging year for the couple, who have documented their three-year struggle with infertility — during which the cancer was discovered — and a heartbreaking miscarriage last year on their Style Network reality series Giuliana & Bill. "Bill and I said, when you strip it all down, it comes down to, do you want to live? And yeah, I do," she says.

But Giuliana's cancer fight has rocked their world like nothing else before. "You go from one minute being in the best spirits," she says, "to an hour later you're crying on your living room floor." The impact of the ordeal "has changed our marriage," says Bill, 40. "The little stuff doesn't matter." The couple's long-held desire to become parents weighed heavily in their decision as well: Opting for a mastectomy also means Giuliana will not likely have to undergo any further treatments that could have induced early menopause or take any medications that would have been disrupted by future fertility treatments.

Even for this "tough Italian woman," as Bill affectionately calls his wife, there are moments of deep grief. Anxiety-stricken when she's alone at night, she now prefers to stay in hotels when Bill is away and can no longer listen to her favorite "sad music," like Adele. But she has retained her sense of humor. Looking at photos taken at the hospital just before her lumpectomies, "I thought to myself, 'Wow, I should keep these pictures. I don't have pictures of my breasts. I've never been in Playboy or anything!'" Now, as the mastectomy and reconstructive surgery approach, "I feel like, move forward. It doesn't really matter what my breasts looked like yesterday." Yes, she'll have scars, "but I think scars tell such an incredible story. I'll always look at them and think, 'Wow, I made it through that.'"

Plans for a baby are "on hold for a little bit. I just have to focus on recovery…I have a lot of things I want to accomplish and a lot of good times that are still to be had," she says. "This is the biggest thing in my life I've had to overcome. But I'm going to come out better than ever. I truly believe that."

*Also In This Week's 'People'*

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-The Jackson 3 – Life After Michael: His Kids Are "Doing Great"
-Jessica Simpson Baby Details: "I Am Honestly Having The Best Time Ever Dressing My Bump