There's a lot wrong with what he said in that interview. So, Denise Richards was talking about HIV in 2006, but he's claiming he found out 4 years ago? Second, he was married 2x since then but he was fukking around with all kinds of pornstars. So, either he had beards or he's lying about only 2 people he's been with.
Richards said she asked Sheen about taking HIV test & taking one herself but didn't really confirm anything. Impossible to know when he really found out.