Monica Lewinsky is promising to reveal secret love letters to Bill Clinton and his penchant for kinky sex in a new tell-all about her days as his favorite intern. Lewinsky, who turns 40 next year, is out for “revenge” and ready to air bombshell details from her Oval Office trysts with the former Horndog-in-Chief in a $12 million memoir, according to friends. Lewinsky never got explicit in past interviews about her Clinton encounters, but now plans to describe his “insatiable desire for three-way sex, orgies and the use of sex toys of all kinds,” one pal told the National Enquirer.