Question: Which person did Brian Jones have a relationship with who also had three children with Keith Richards?
Context: Stoned, also known as The Wild and Wycked World of Brian Jones in the UK, is a 2005 film about Brian Jones, one of the founding members of The Rolling Stones.  The film is a cinematic work of historical fiction, taking as its premise the idea that Jones was murdered by Frank Thorogood, a builder who had been hired to renovate and improve Jones's house Cotchford Farm in East Sussex.  The film also paints a picture of Jones's use of alcohol and drugs, and his relationships with Anita Pallenberg and Anna Wohlin. Charles Robert Watts (born 2 June 1941) is an English drummer, best known as a member of the Rolling Stones.  Originally trained as a graphic artist, he started playing drums in London’s rhythm and blues clubs, where he met Brian Jones, Mick Jagger, and Keith Richards.  In 1963, he joined their group, the Rolling Stones, as drummer, while doubling as designer of their record sleeves and tour stages.  He has also toured with his own group, the Charlie Watts Quintet, and appeared at London’s prestigious jazz-club Ronnie Scott’s with the Charlie Watts Tentet. "2000 Light Years from Home" is a song from The Rolling Stones' 1967 psychedelic rock album "Their Satanic Majesties Request".  Written by Mick Jagger and Keith Richards, it also appeared as the B-side to the American single "She's a Rainbow", and charted as a single in Germany.  Jagger reportedly wrote the lyrics in Brixton prison following his conviction on drug charges in June 1967.  The song was recorded by the band inside Olympic Studios during July 1967.  The working title of the instrumental backing was "Toffee Apple".  The prominent string part is played by Brian Jones on Mellotron. "Please Go Home" is a song by British rock 'n' roll band, The Rolling Stones.  It was written by Mick Jagger and Keith Richards and recorded in August 1966.  It first appeared on the UK version of "Between the Buttons" but was left off the US version in favor of the two hit singles, "Let's Spend the Night Together" and "Ruby Tuesday".  The song later appeared in the US on the album, "Flowers".  "Please Go Home" mixes a heavy Bo Diddley beat, played on a tremolo guitar by Brian Jones revisiting his guitar work on "Mona", the usual Stones female put downs, and psychedelic flourishes, such as heavy repeating echo at the end of each line of the chorus.  It also features an oscillator, played by Jones.  The song has been covered by Izzy Stradlin. Anita Pallenberg (6 April 1942 – 13 June 2017) was an Italian actress, artist, and model.  A style icon and "It Girl" of the 1960s and 1970s, Pallenberg was credited as the muse of the Rolling Stones: she was the romantic partner of Stones multi-instrumentalist Brian Jones, and later, from 1967 to 1980, the partner of Stones guitarist Keith Richards, with whom she had three children. The Rolling Stones are an English rock band formed in 1962.  They have released 25 studio albums through 2016.  The original lineup consisted of multi-instrumentalist Brian Jones, lead vocalist Mick Jagger, guitarist Keith Richards, bass guitarist Bill Wyman, drummer Charlie Watts, and keyboardist Ian Stewart.  Stewart was dismissed from the lineup in 1963, but continued to serve as their road manager and de facto keyboard player.  Following Jones' death in 1969, Mick Taylor took over lead guitar duties until 1974, when he quit the group over issues of songwriting credits.  He was replaced by ex Faces guitarist Ronnie Wood.  The band was inducted into the Rock and Roll Hall of Fame in 1989.  The group continues to write, tour, and produce to this day. "Stray Cat Blues" is the eighth song on the Rolling Stones' album "Beggars Banquet".  It was written by Mick Jagger and Keith Richards and produced by Jimmy Miller.  Miller's production of the song is very representative of his style, featuring a very prominent hi hat beat, droning piano performed by Nicky Hopkins, a mellotron performed by Brian Jones, all electric guitars (including slide) performed by Richards and vocals from Jagger kept even in the mix.  According to Mick Jagger, the song was inspired by "Heroin" by the Velvet Underground.  The intro of Stray Cat and Heroin are similar. Aftermath, released in April 1966 by Decca Records, is the fourth British studio album by the Rolling Stones.  It was issued in the United States in June 1966 by London Records as the group's sixth American album.  The album is considered an artistic breakthrough for the band: it is the first to consist entirely of Mick Jagger–Keith Richards compositions, while Brian Jones played a variety of instruments not usually associated with their music, including sitar, Appalachian dulcimer, marimbas and Japanese koto, as well as guitar, harmonica and keyboards, though much of the music is still rooted in Chicago electric blues.  It was the first Rolling Stones album to be recorded entirely in the US, at the RCA Studios in California, and their first album released in true stereo.  It is also one of the earliest rock albums to eclipse the 50-minute mark, and contains one of the earliest rock songs to eclipse the 10-minute mark ("Goin' Home"). The Rolling Stones are an English rock band formed in London in 1962.  The first stable line-up consisted of Brian Jones (guitar, harmonica), Mick Jagger (lead vocals), Keith Richards (guitar, backing vocals), Bill Wyman (bass), Charlie Watts (drums), and Ian Stewart (piano).  Stewart was removed from the official line-up in 1963 but continued as a touring member until his death in 1985.  Jones left the band less than a month prior to his death in 1969, having already been replaced by Mick Taylor, who remained until 1974.  After Taylor left the band, Ronnie Wood took his place in 1975 and has been on guitar in tandem with Richards ever since.  Following Wyman's departure in 1993, Darryl Jones joined as their touring bassist.  Touring keyboardists for the band have been Nicky Hopkins (1967–1982), Ian McLagan (1978–1981), Billy Preston (through the mid-1970s) and Chuck Leavell (1982–present).  The band was first led by Jones, but after teaming as the band's songwriters, Jagger and Richards assumed leadership while Jones dealt with legal and personal troubles. Keith Richards (born 18 December 1943) is an English guitarist, singer, songwriter, and author, best known as a founder member of the rock band the Rolling Stones. " Rolling Stone" magazine credited Richards for "rock's greatest single body of riffs" on guitar and ranked him 4th on its list of 100 best guitarists.  Fourteen songs that Richards wrote with the Rolling Stones' lead vocalist Mick Jagger are listed among "Rolling Stone" magazine's "500 Greatest Songs of All Time".  The Stones are generally known for their guitar interplay of rhythm and lead ("weaving") between Richards and Brian Jones, Mick Taylor and Ronnie Wood over the years.  In spite of this, Richards plays the only guitar tracks on some of their most famous songs including "Paint It Black", "Ruby Tuesday", "Sympathy for the Devil" and "Gimme Shelter".
Answer: Anita Pallenberg