LeAnn Rimes tells Us Weekly she's waiting to have kids with Eddie Cibrian because she's "still young and fertile." Credit: Gregg DeGuire/FilmMagic

LeAnn Rimes and Eddie Cibrian have their hands full with Mason and Jake, the actor's sons with ex-wife and Real Housewives of Beverly Hills star Brandi Glanville. Even so, the spouses of two years are excited about the prospect of starting a family of their very own.

"We talk about having kids all the time and I would love to, but it's gonna be a second," Rimes tells Us Weekly. "I'm still young and fertile -- it's all good!"

The "Borrowed" singer predicts that Mason, 9, and Jake, 6, will be "a little older" before she and Cibrian give them a half-sibling. "I was just with the kids for the last two days taking care of them on my own, and trust me . . . I have a newfound respect for working moms who do it all by themselves," Rimes admits. "It was my birth control for a little bit -- so overwhelming!"

The tight-knit brothers are "really active," Rimes explains, so most afternoons are spent hanging out in the backyard playing "whatever they're dreaming up at that moment."

"The little one has a vivid imagination, so we're usually playing swords and shooting people with imaginary guns. Mason is turning 10 and he's definitely got that kind of pre-teen thing going on, which is so crazy because I've known him since he was 6," the Grammy winner tells Us. "They ride dirt bikes now and quads. I grew up in Mississippi, so I've ridden quads my whole life, since I was like 2-years-old. So that's kind of like our family thing to do now. Everybody has either a dirt bike or a little quad and we go riding around the neighborhood."

Rimes, 30, doesn't mind being outnumbered 3-to-1 when Cibrian has custody of the kids. "It's fun to be around boys," explains the singer,  whose new album Spitfire is out June 4. "You get to do things that I didn't necessarily get to do and haven't gotten to do in a long time. With two boys around, I usually don't get out of shorts and a T-shirt because we're rolling around most of the time and jumping on a trampoline. I love it!"