By Jennifer Garcia/Los Angeles Linda Marx/Miami Charlotte Triggs/Los Angeles Aili Nahas/Los Angeles Elizabeth Leonard Cynthia Wang/Los Angeles and Ken Lee/Los Angeles
Updated February 14, 2011 12:00 PM

For those who know Charlie Sheen, the situation was all too familiar. He’d been rushed to the hospital early on Jan. 27 with severe abdominal pain after a wild two days reportedly spent partying at home with porn stars and cocaine-but hours later the Two and a Half Men star was already brushing off the incident. “He was really casual about it,” a pal says of the actor, who left the hospital later that day, after assuring friends he would get help. Instead, back in his Beverly Hills mansion, Sheen, says the source, seemed ready for round two, joking, “‘Where are the girls?'”

Over the next days, with close pals and relatives (including Sheen’s father, actor Martin Sheen, and his ex-wife Denise Richards) urging him to get help, the gravity of his situation finally hit home. “With the help of friends and family, he agreed to go into rehab,” Sheen’s manager Mark Burg told PEOPLE. While Sheen’s rep first announced on Jan. 28 that the actor “has voluntarily entered an undisclosed rehabilitation center,” Sheen, 45, opted instead to undergo an unorthodox course of individual treatment for the foreseeable future. (He is currently under treatment at home.) “He has tried [inpatient] rehab, and it didn’t work, so he is trying something different,” says Burg of Sheen, who has already been treated for substance abuse three times over the past 20 years (most recently last February). “Charlie has put together a team that he trusts, including [a top] drug intervention specialist, counselor, registered nurse, sober companion and security to help get him sober once and for all.”

His decision to seek treatment caps a turbulent year for the actor, who was arrested in December 2009 for domestic violence against ex-wife Brooke Mueller (he pleaded guilty to misdemeanor assault and was sentenced to 30 days of rehab) and was hospitalized for “alcohol abuse and a psychological evaluation” when he allegedly trashed a New York hotel room during an argument with a porn star in November. “He doesn’t think he’s going to die. He doesn’t want to stop,” says a source of his prerehab mind-set. “He thinks, ‘I’m having fun, so what? I’m making $2 million a week. I show up for work. What’s the problem?'”

Until now he had somehow managed to pull off his work-all-day, party-all-night lifestyle. Sheen remains one of the most popular and highest-paid actors on television, earning a reported $1.8 million per episode for [Two and a Half Men], TV’s top-rated comedy. His [Men] colleagues have long marveled at Sheen’s skillful ability to keep his personal problems away from the set. “Charlie’s been nothing but a professional,” says a show source. “He’s friendly, he shows up on time and does his job.” Because Sheen’s public antics never disrupted production-his hospital visit took place while the show was on a scheduled hiatus-sources say, the network had no immediate reason to intervene. Says a pal: “He was self-destructing, and in a way they enabled him by letting the show go on without consequences.”

But as reports of his self-destructive behavior continued to mount (see box), CBS executives grew increasingly alarmed. “This man is a father, so obviously there’s concern on a personal level,” CBS Entertainment president Nina Tassler told reporters last month. “But you can’t look at it simplistically. On a professional level, he does his job.”

Sheen himself quite enjoys the notoriety that comes with his bad-boy reputation, says the source: “He loves to shock people.” Which he seems to do with some regularity. “The stuff you hear is unbelievable,” costar Jon Cryer told Conan O’Brien of Sheen’s antics, in an interview one day before Sheen’s Jan. 27 hospitalization. “You [read something and] you’re thinking, ‘Wow, I sure hope Charlie’s okay,’ and he comes into work and [says], ‘Well, I’m doing okay, except that somebody stole my car and ran it off a cliff last night.’ Normally you wouldn’t believe that from somebody, but [you believe] Charlie Sheen because that happened to him-twice.”

Yet in recent months friends seemed to be growing weary of his behavior. “When you are his age, and you are a father, it’s just ridiculous,” says the source. Sheen’s daughters Sam, 6, and Lola, 5, with his ex-wife Denise Richards, are becoming increasingly aware of their dad’s public profile. (Says the source: “Denise has done her best, but she can only keep so much from them.”) As for Sheen’s twins with Mueller, Bob and Max, 22 months, “they’ve been being cared for by their mother and a nanny, and nothing changes with Charlie entering rehab,” says a source close to Mueller.

This last incident, which resulted in his second hospitalization in three months, left friends seriously concerned. “He scared the s— out of people,” says the friend. Sheen had allegedly been partying for two days with guests that included porn star Kacey Jordan and had smoked cocaine, Jordan tells PEOPLE. (A rep for Sheen refused to comment on specifics, saying, “I don’t respond to speculation or rumor.”) “He did not OD,” adds the source, “but yes, he was partying.” Around 6 a.m., the actor, who also struggles with a hernia, began having “severe stomach pain,” says the source. “It’s like his body seemed to be starting to shut down. It’s too much.”

Guests called Sheen’s friend and neighbor Dr. Paul Nassif, husband of Real Housewives of Beverly Hills star Adrienne Maloof-Nassif; Nassif instructed them to call an ambulance and also phoned 911 himself. “He was in serious condition,” says the friend. “It was a scary situation.”

Though Sheen’s initial public statement after leaving the hospital said he planned to return to work when Men production was scheduled to resume four days later, his close circle intervened. With both of his parents and Denise Richards on hand at the hospital and later at his estate, “everyone wanted to take an aggressive stance,” says the friend.

And when CBS execs finally got involved, “they put big pressure on him to go to rehab, and that was the final trigger,” says the friend. “He always thought as long as he did his job, nothing else mattered, so until the show put pressure on him, he was in that mind-set.”

With Sheen out of commission, production on this season’s remaining eight Two and a Half Men episodes has halted. “We are profoundly concerned for his health,” said executive producer Chuck Lorre. But filming will resume at the end of February “as long as Charlie tests clean,” says a show source. “His team in place thinks it’s a positive thing for Charlie to continue to work.”

As Sheen begins his latest treatment, experts hope that he will take rehab seriously this time. “When people who have some degree of significant recovery go back to treatment, they’re actually harder to treat. They start saying, ‘Well, I know what I have to do; let me out of here,’ ” says addictions expert Dr. Drew Pinsky, who is skeptical about Sheen’s choice of individual instead of group treatment. “Treatment of addiction is a group process when done properly, not an individual thing at all,” he says, adding, “Half measures usually end up in trouble.”

His family and friends, however, are hoping for the best. “Charlie is a really nice person with a heart of gold, but the demons are within himself,” says a close Sheen friend. “A lot of people in his life are really trying to make sure he takes care of himself.” Burg is confident that Sheen will do just that. “He has finally decided,” says Sheen’s manager, “it’s time to shut the party down.”