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Playboy founder Hugh Hefner has had countless lovers over the years — some more notable than others. Here's a chronological history of the wives, girlfriends, and Bunnies who found themselves in his bed. Because Hef has never been a one-woman man, there's a lot of overlap.

2. Mildred Williams (1949-1959)

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Hef married his first wife in 1949. Mildred cheated on Hugh while he was in the Army, but she later gave him a free pass for sleeping with other women.

3. Donna Michelle (c. 1963-1964)

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1964's Playmate of the Year Donna Michelle was only 17 when she first posed nude in Playboy. She died in 2004.

4. Barbi Benton (1969-1976)

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Partnered for eight years, Barbi and Hugh met on the set of Playboy After Dark. Hef later said that meeting Barbi was his favorite memory of doing the show.

5. Unknown Men (c. 1960s)

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In 1971, Hugh revealed that after his divorce, he became a swinger and experimented with bisexuality.

6. Karen Christy (c. 1971)

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Karen Christy was Playmate of the Month in the December 1971 issue.

7. Marilyn Cole (c. 1971-1974)

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1973's Playmate of the Year Marilyn Cole was the first full-frontal nude centerfold in the magazine. Hef obviously saw something he liked.

8. Lillian Muller (c. 1974-1976)

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When not dating Hugh Hefner, Lillian made her mark in the music video world, appearing in Van Halen's "Hot For Teacher" and Rod Stewart's "Da Ya Think I'm Sexy?"

9. Sondra Theodore (1974-1981)

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After moving into the Playboy Mansion, Sondra was lucky enough to be one of the "Singing Playmates."

10. Carrie Leigh (1983-1988)

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Probably not one of Hugh's favorite exes, Carrie filed a $35 million paternity suit against Hef.

11. Shannon Tweed (1982)

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Shannon and Hef only dated for a year. In 1983, she moved in with Gene Simmons — and they've been together ever since.

12. Kimberley Conrad (1989-2010)

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Hugh's longest marriage was to Kimberley Conrad, with whom he had two sons. They separated after nine years but stayed married until 2010.

13. The Bentley Twins (1999-2000)

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Sandy and Mandy were the first of Hugh's live-in twin lovers. After leaving Hef, Sandy became involved with Mark Yagalla, who was later arrested for conducting a Ponzi scheme.

14. Brande Roderick (2000-2001)

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Before appearing in Playboy, Brande was a cast member on Baywatch. Since then, she's competed on Celebrity Apprentice.

15. Tina Marie Jordan (2001-2002)

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Tina Marie made several appearances on The Howard Stern Show, both before and after she became a Playmate.

16. Izabella St. James (2002-2004)

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Polish Playmate Izabella is best known for writing a tell-all memoir Bunny Tales: Behind Closed Doors at the Playboy Mansion, the first book written by one of Hugh's exes.

17. Bridget Marquardt (2002-2008)

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One of the Girls Next Door, Marquardt was never actually a Playboy Playmate. There are still plenty of nude pictures of her online.

18. Holly Madison (2003-2008)

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Another one of the Girls Next Door, Holly broke up with Hef because he wouldn't put a ring on it. She has since moved on to other reality TV endeavors.

19. Kendra Wilkinson (2004-2009)

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Kendra lasted longer than the other Girls Next Door, but she and Hugh eventually parted ways. Now going by her married name Kendra Baskett, her current series is Kendra on Top.

20. Kristina and Karissa Shannon (2009-2010)

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Along with Crystal Harris, Kristina and Karissa were Hef's rebounds after his break-up with Holly. They also appeared on The Girls Next Door.

21. Crystal Harris (2009-2011, 2012-)

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Crystal and Hugh have been on-again, off-again, but now they're officially married. Their New Year's Eve wedding was held at the Playboy Mansion.