Charlie Sheen reportedly only discovered he is HIV-positive "long after" splitting from Bree Olson.

Charlie Sheen

Charlie Sheen

The 50-year-old actor, who was diagnosed with the virus four years ago, insists the former porn star ended their relationship via text message before doctors gave him his test results in 2011 even though she claims they were living together around the same time.

Charlie's manager Mark Burg told PEOPLE.com: "Bree Olson is all over Howard Stern but the truth is she wasn't in Charlie's life when he was HIV-positive and so there was no reason to tell her anything."

A source close to the 'Anger Management' star also told gossip website TMZ.com that he is aware many of his sexual partners are lining up to sue him for allegedly exposing them to the disease, but claims Bree, 29, doesn't have a case because Charlie only found out after he returned to Los Angeles from his Violent Torpedo of Trust US tour, which ended on May 3, 2011, almost two weeks after she broke up with him.

While Bree has been given a clean bill of health from her doctors, she has branded her ex-boyfriend "a monster" for allegedly putting her life at risk.

She told 'Inside Edition': "He is a monster, and he put my life in jeopardy along with hundreds -- or potentially thousands -- of other women's lives."

Charlie, who has five children from three different relationships, told his eldest daughter Cassandra, 30, about his diagnosis before going public with the news, but decided to not to discuss it with daughters Sam, 11, and Lola, 10, or six-year-old twins Bob and Max.

A source close to the star told UsMagazine.com: "He didn't tell the kids because they are so young and wouldn't understand."