On September 8, Whitney Houston, 43, filed for separation from husband Bobby Brown, 37, citing "irreconcilable differences" and taking the first step in ending a tumultuous 14-year marriage.

Though a source close to the couple says Houston and Brown have talked divorce "dozens of times," they never set the legal process in motion. Why the big step now?

Sources tell Us Houston came to the conclusion that her rocky marriage - complete with infidelity and dwindling finances - was finally over after a dramatic intervention led by Houston's music-biz mentor, Clive Davis (who was prompted to intervene at the behest of singer, Courtney Love who recommended that Houston work with her own addiction coach, Warren Boyd).

"Getting sober has given her the clarity to move on from him," a source close to Houston tells Us. Adds another source close to the couple, "After all these years, she cleaned up and got smart. She didn't need him and realized it.” (Reps for Houston and Brown had no comment.)