The 38-year-old actress and 44-year-old actor discussed their sex life and the secrets to their lasting relationship in the April 1 issue of People.
Bell and Shepard said they enjoy bantering with each other and getting fired up in debates.
"I wouldn't say we need spicing up. We haven't had to turn to leather accoutrements or anything," Shepard told the magazine. "It's still functioning quite well."
"I didn't marry you for your pecs," Bell said. "We stimulate each other a lot with debates, and the great thing is we disagree on 99.9 percent of topics on the planet. There's always spice to be had."
The CHiPs co-stars said they remain physically attracted to each other but don't focus on looks.
"What's funny is Kristen will see CHiPs and go, 'Oh, you really got in good shape for that movie!' I was like, 'Yeah, I was in your bed in that shape. It'll just hit her when she sees it. She doesn't notice if I gain or lose 20 pounds,'" Shepard said.
Bell and Shepard married in October 2013 and are parents to two daughters, 5-year-old Lincoln and 4-year-old Delta. The couple shared an emotional moment on The Ellen DeGeneres Show in January after Shepard was asked what he recommends getting a loved one for their birthday.
"Please, please please give that person love and support for 11 years. Give them two beautiful baby girls -- and you're good," the actor said with Bell in the audience.
Bell and Shepard launched their own baby product line, Hello Bello, in February.