LOS ANGELES - Playboy magazine founder Hugh Hefner, host to an ever-changing coterie of scantily-clad young women at the Playboy Mansion, has filed for divorce from the estranged wife who many people forgot he had ever married.

Hefner, 83, filed court documents last week seeking to end his marriage to former Playmate Kimberley Conrad, 47, citing irreconcilable differences.

The documents, obtained by celebrity website TMZ.com on Wednesday, said the pair were married in July 1989 and have been separated since January 1998.

Conrad and Hefner have two sons. Since their separation, Conrad and the boys have lived in the house next to the famed Los Angeles Playboy Mansion where Hefner resided with several girlfriends and stars in the TV reality show The Girls Next Door.

I am happy to be out of the marriage. I only remained married (to Conrad) for the sake of the children, at her request. I am happy to have this behind me, Hefner told TMZ in a telephone interview on Wednesday.

Hefner's decision to seek a divorce follows court action in August by Conrad, who filed a $5 million lawsuit against the Playboy founder relating to the sale of a house they owned together. Hefner told TMZ.com he owed nothing to Conrad, saying he had been generous to a fault.

The documents obtained by TMZ.com gave a glimpse into the lifestyle of Hefner, who earlier this year installed 19-year-old twins into the mansion as his girlfriends at the end of the fifth season of The Girls Next Door.

According to the documents, Hefner has assets of more than $43 million, excluding Playboy stock and property, and spends about $43,000 a month on food and entertainment.

Hefner has asked for spousal support for Conrad to be set at $20,000 a month, saying he has already given his estranged wife close to $12 million since their separation 11 years ago.

Hefner began publishing Playboy magazine in 1953. Profits from the adult entertainment business Playboy Enterprises Inc, which includes TV networks and licensing deals for pink bunny ears, have declined in recent years due to competition from free adult material on the Internet and a drop in advertising revenue.

Playboy Enterprises appointed a new chief executive in June to replace Hefner's daughter Christie, who left after two decades. Hugh Hefner remains editor-in-chief of Playboy magazine and retains overall control of the company.

(Editing by Will Dunham)