Sad now.
Sorry. I've been reading Angela Bowie's tell-all bio and she didn't say anything about it, and she certainly would have.
My favorite bit wasn't about her finding Mick in bed with David, but rather when the Bowies came to NYC and she grabbed Billy Murcia (then the drummer with the Dolls) and he grabbed Cyrinda Foxe (at the time, David Johansson's girlfriend) and they shacked up in a Manhattan hotel suite for a week long debauch. Bowie later used Cyrinda in the "Jean Genie" video, shot partly in San Francisco.
Lou had a beautiful trans companion for a couple years there in the early seventies, and then had a brother/sister set of lovers at one point.
By the by, a lot of glam era movies and video have been making it to the market lately including a live concert of Lou in Paris from about '73 (so Live Animal era) doing hard rock versions of VU songs. Also the Ballad of Mott is supposed to be great, and Alice Cooper's Billion Dollar Babies tour film came out on DVD.
I've got Marc Bolan's mid-seventies kids show (Marc) on VHS and you can get it bootlegged on DVD. There's a great compilation of Dolls video available and the Musikladen twofer of Roxy Music (w/ Eno) and T.Rex is fantastic.