The latest episode of actor Kareena Kapoor Khan's radio show, What Women Want, features her husband and actor Saif Ali Khan. During the conversation, which revolved around modern marriages, Kareena asked Saif what is the one thing that couples should do to keep the spark in their marriage alive.

"Role play," Saif responds, leaving Kareena speechless. She manages to recover and says, "Actually, we have spoken about every possible topic on the show, so it's fine," even as Saif clarifies that he was joking.

Saif then goes on to say that "different interests" play a major role in keeping the spark alive: "If you have slightly different things to do, if there is a little bit of freshness when you meet at the end of the day or after a couple of days, if you have some new ideas to swap… I think repetition and a mundane kind of existence is a bit worrying for everybody because any long-term relationship can get a bit repetitive."

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Saif also said that one should not constantly feel the pressure of keeping the spark alive. "It's a really scary thing. Like Woody Allen said, 'I can't keep up the same level of charm for 10 years. I'll have a heart attack.' It's okay. Sometimes, you have to find ways to keep your own spark alive," he said.

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Kareena complained that Saif often promises to take her out to dinner but comes home tired and cancels the plan. "Laziness is a villain generally in life, you know. People say 'Love is a verb' and it's something that has to be shown in practice. Even if you don't feel like it and you go and pick someone up from the airport once in a while, it just makes things nicer," he said.

"You should do that as well!" Kareena exclaimed, as Saif smiled sheepishly. "Clearly, you're not keeping the spark alive. It's been 11 years, you haven't bothered to (pick her up from the airport)!" she said.

Saif said that he went to receive Kareena at the airport once. "I picked you up once because your mother called and said that there is trouble in London or something," he said, to which she remarked that it was a decade ago. He begged to differ and said that it had just been three years.

For Saif, a successful marriage is all about maintaining the balance between personal and professional life. "People have compared marriage to a base camp and if you want to climb mountains, you need a good base camp before you climb. But if you spend all your time climbing mountains, there will be no base camp left," he said.

Saif and Kareena, who fell in love during the making of their 2008 film Tashan, got married on October 16, 2012. They have a three-year-old son, Taimur.

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