Kathy Hilton has never been apart from her husband for more than two weeks

She told People: "We're best friends. And, I was just saying to someone, getting married so young like that - I was 19 and he was 23 - [the key is] just keeping the right people around you, the right influences and being around other couples who are happy [and] have the same values as you. We have not been away from each other for two weeks in [all our years] of marriage."

The 'Real Housewives of Beverly Hills' star - who has Paris, 43, Nicky, 41, Barron, 35, as well as 30-year-old Conrad with Richard - noted that the pair of them don't go to bed on an argument and always try to "keep a little mystery" in their marriage to keep the spark alive.

"I don't think you go to bed without saying, 'I love you,' and giving each other a kiss and never in a fight or anything. If you have had a disagreement, you always make up before you go to sleep and keep a little mystery and always keep it exciting and fun.

For their anniversary celebrations, Kathy and Richard went on a trip to Paris and London, and she revealed that she indulged in the British appetizer of pigs in blankets, which are a festive tradition made up of chipolatas wrapped in bacon, as they flew back from the English capital.

She said: "We did five days in Paris and seven days in London. It was shocking, it was gorgeous. My husband put it on his Instagram. One thing I do love, and it's always at all my parties all through the years, are pigs in a blanket and I didn't realize the Brits - that's part of their Christmas dinner. So I got another pig in a blanket [on the plane]."