By Sabrina Ford

NEW YORK (Reuters) - Fans of the bestselling novel "Waiting to Exhale" may have been holding their breath for a sequel all these years, but author Terry McMillan never thought she would revisit her most famous characters.

"I had not intended to write a sequel about these women. Not at all," says McMillan, 58, of the four black 30-something women whose stories of love, affairs, fires and friendship were told in 1992's "Waiting to Exhale" and are reprised in "Getting to Happy," published in the United States this week.

In 2005, McMillan endured a very public divorce after her much younger husband revealed he was gay. Their happier times were the inspiration of her 1997 novel, "How Stella Got Her Groove Back." McMillan says the pain of their divorce helped push her to write "Getting to Happy."

"After going through a horrible three years post-divorce, I went on tour for my last book and came across a lot of women who were sad," McMillan told Reuters in an interview.

"I started thinking about women who were pushing 50 and may be experiencing loneliness and boredom, or those who'd experienced deception, like I had."

While considering writing a book that would focus on the experiences of middle-aged women, McMillan had a revelation.

"It dawned on me that I had already chosen four characters through which to tell this story. It hit me that with where I left off the women in "Waiting to Exhale" -- they may very well be good candidates."

"Getting to Happy" picks up with Bernadine, Savannah, Robin and Gloria, 15 years after we last saw them and fills readers in on what they've been up to all this time. In order to pick up where she left off, McMillan, who "never" re-reads her work, had to revisit "Exhale," a necessary task she dreaded.

"I would cover my face, sitting in my own office saying, 'Terry, you did not write that!,'" said McMillan. "Some of it was embarrassing. I thought in some cases the characters were a little bit vulgar. But I try not to censor myself when I'm writing through characters. I let them tell do the talking and tell the story."

In the most famous scene from "Exhale" and the 1995 movie adaptation, Bernadine, played by Angela Bassett, torches her philandering husband's car on the front lawn of their home.

McMillan continued to let the women she created tell their own stories in "Getting to Happy."

"I put (the characters) in these situations but, I didn't know how they'd get out of them or how they'd deal with everything. If I knew that I wouldn't have wasted my energy writing it," she said.

Film rights to "Getting to Happy" have been optioned to the production team behind the "Exhale" movie -- which also starred Whitney Houston -- and McMillan has completed work on the first screenplay draft.

"We want the same cast," McMillan said. "I think they're pretty interested ... It would be very, very nice."