For a long while, the major distinction of Fleetwood Mac was not cashbox success but rather that it was the most groupie-proof rock group on the road. Co-founder drummer Mick Fleetwood was a joyously married father of two. John McVie, his co-captain, was wed to the Toni Tennille of hard rock, Christine, the outfit's keyboardist and one of its singer/songwriters. And lately joining those Brits were two Californians, inventive lead guitarist Lindsey Buckingham and his own lady of eight years, Stevie Nicks, a singer-writer, too, and electric onstage writher.

The group enjoyed only modish attention in the States until suddenly last fall Chris's creamily smooth Over My Head became a smash single. A tumultuous tour made the quintet's first joint, superbly diverse LP, Fleetwood Mac, into a colossal platinum hit. After an astounding 41-week stay on the charts, sales are soaring toward two million.

Chris, 32, who, with Stevie, has added a softened, more melodic feel to the Mc Vie-Fleetwood rock bottom, confesses, "I'm mystified. I just write songs by stepping into other people's shoes. Lyrics derive from relationships around me. That makes it easier to write love songs."

Sadly, Chris may find that sort of material increasingly scarce. Love has kept the Captain and Tennille together, but, after seven years, road fever has put the Fleetwood Mac members personally (if not professionally) asunder. The McVies broke up late last year. Fleetwood and his ex-model wife, Jenny, are getting divorced, and the Buckingham-Nicks nonmarital arrangement ended just last month.

"We married two years before I joined the group," Chris recaps calmly. "Then I joined in 1970 and we were together all the time. But after five years on the road seeing each other at our worst, we never had that space to step back, to enjoy missing someone—that sweet sorrow trip. Otherwise, you can go insane. We were Siamese twins. 'Hi Chris, where's John? Hi, John, where's Chris?' " The wisest perspective on what happened comes perhaps from John. "It was very heavy for a couple of months," he says soberly. "But what matters now is accepting what's left between us. Look, man, we were together every second for more than five years, 365 days a year, 24 hours a day, in the studio, on the road, during time off. In anyone else's scene, we were married for the equivalent of 40 years."

Chris wants now "to be in a vacuum, to have no problems," and like all five Macs, to get on with the music and transcend any centrifugal peevishness that could corrode their platinum status. John has a new lady now, but he reports with unmistakable affection that "Chris's reaction to the whole thing has been extremely mature."

Only a hardily seasoned and disarming wit could have enabled her to survive the road life all these years. Born Christine Perfect in England's Birmingham, she had to put up with even more nameplays at school than Chevy Chase. Her father, a music professor who gave violin recitals at cathedrals, urged her on to a career in classical piano. But by 12, Chris "loathed piano," went to art school for five years and "finished as a uselessly qualified sculptress." By then her musical tastes had been secularized by the Everly Brothers and black blues artists like B. B. King and Otis Spann. To escape deepening boredom as a London department store window dresser, she joined a local club band, Chicken Shack, and shortly thereafter fell in love with McVie. Along with Fleetwood, he had played with John Mayall's Bluesbreakers on the mid-'60s English blues club circuit.

"It takes stamina to stay in rock," says Chris. "Lots of girls try it and slip by the wayside. You have to take care of yourself and avoid the weird drugs, or even the heavy-duty Southern Comfort stuff. You can definitely fall down and end up in an asylum. But I don't see why a girl couldn't sit down and learn lead guitar," she continues. "I daresay to a guy it'd be rather sexy," she adds, mock-riffing on an imaginary ax. "But I guess it is a bit butch. I like to retain my femininity, even in jeans [she has 40 pairs]. I don't want to come off the least bit lezzo—leather jumpsuits and all that."

A new LP is near ready, but luxuriantly being held while Fleetwood Mac thrives, and a summer tour is planned. And money is also coming in from previously frozen oldie revenues. It was held up by a still unsettled court battle against an ex-manager who sent out a bogus "Fleetwood Mac" group. "Money is frightening," admits Chris, who plans to move from a rented apartment in Hollywood and buy a home. "I like to spend it as it comes in as long as I can pay taxes and live comfortably." (She's a tax exile from the U.K. where she would be in the 83 percent bracket.)

Road life has toughened Chris. "You have to detect the real friends from the lurking creeps with ulterior motives. Female groupies line themselves up for me—not sexually, thank God—and they turn out to be people who (a) write poetry, (b) write songs, (c) want to be palsy-walsy with me or (d) fancy the drummer." But for now Chris and comrades can cope with the peculiar perquisites—and domestic pains—of hard-won rock fame. "It's all just another chapter of weird Mac karma," muses the dry, laconic Fleetwood. "We all got it on so right, musically, from the start—and we all have ended up biting the emotional shoulder."