'19 Kids and Counting' star Michelle Duggar on how she and husband Jim Bob keep the flame alive

Jim Bob and Michelle Duggar of TLC's "19 Kids & Counting." (Discovery Communications)

"19 Kids and Counting" mom Michelle Duggar has another tip for keeping the flame going in a marriage. Keep your spouse on their toes.

When asked by a Facebook fan for "inexpensive date night ideas," Michelle reveals that she and her hubby of 30 years keep it simple and just "go for a drive and just park and talk or take a walk and talk."

She also dishes about her husband's wilder side. "Jim Bob is so much more spontaneous than I am," she writes on the family's blog. "I like to plan ahead and think about it for days and always have my ducks in a row. But I've learned to just jump and go; it’s so much more fun that way."

The TLC star gushes, "If we've got something happening on our regular date night, Jim Bob usually will just call me up on a weekday and ask me out on a date. It’s really sweet, he’ll call up and say, 'Hey, can I come and steal you away for a date?' Then he’ll surprise me and take me for lunch between his office work and my work at home."

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However, it took Michelle some time to get used to her husband's flexible nature. "For a while it was really hard for me, because I'd think, 'Wait a minute, we can’t do that. I'm not prepared. I've got to get all these things done,'" she admits. "And I realized that was squelching Jim Bob’s creativity and fun spirit -- both things that I really love about him. I had to let go of that urge to plan everything. And when I did, it brought such a wonderful new dimension to our marriage."

As for the couple's perfect date night, it should come as no surprise that the parents of nine girls and 10 boys enjoy "when it’s quiet and there are no interruptions." Michelle adds, "We really enjoy that because we’re not around a lot of people then, and we can catch up with each other. Other times, we’ll go out for a coffee or ice cream, which is my favorite weekly sweet treat, or occasionally a nice meal."

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Michelle's big tip, "You really do need to be flexible with each other and spontaneous in your relationship."