AceShowbiz -

For the umpteenth time, Charlie Sheen's ex-wife Brooke Mueller checked into a rehab facility. The 38-year-old is seeking treatment for unknown cause but reports said Sheen's recent HIV diagnosis was partly blamed for her relapse.

Sheen shocked the world when he admitted in November that he was positively diagnosed with HIV four years ago. Saying he didn't "entirely" know how he contracted the virus, the actor dated Bree Olson and got engaged to Brett Rossi around that time. However, Sheen denied he was already HIV positive when he was in a relationship with Olson.

Time-wise, Mueller was safe from the virus because she split from Sheen in late 2010. She and their twin boys Bob and Max are not expected to have HIV but the news still devastated her. "Brooke had a very difficult time in the immediate aftermath of Charlie's situation going public," a source told Radar Online. "Even though she and the twins don't have HIV, it just brought back a lot of very bad memories of the time when Brooke was married to Charlie."

Mueller had been treated for addiction to cocaine and alcohol in the past. She had entered rehab multiple times and had been arrested on both cocaine possession and assault. "The relapse was swift and apparent to everyone immediately," the insider added. "Within two weeks of the relapse, Brooke decided to go to rehab herself. This was a huge step because Brooke recognized it."

There's no official detail about her rehab stay but rumor has it the facility is in Utah and it will take at least four months for Mueller to complete the program.