THERE WAS SOMETHING heart-ending in the spectacle of Billie Jean King appearing at a press conference to inform the world that she had, indeed, had an affair with the woman who is now suing her for support. Here was Billie Jean King, who brought money and stature to women's tennis and who became a symbol and heroine of the women's movement in the process, making an unprecedented public admission that was bound to hurt her, her husband and her family, and that would clearly play into the hands of those who put down women athletes by endowing them with imagined masculine traits. She had everything to lose in that 20-minute press conference, but unlike other public figures who have gotten caught in private indiscretions, Billie Jean King took responsiblity for her actions with honesty, grace and courage. j

What Billie Jean King does in private is arguably nobody's business and, in an ideal world, nobody would give a hoot what she does off the court. But public figures pay a price for that elevated station in life, whether they are congressmen, athletes or movie stars. The more famous they are, the more interested we are in them. A useful journalistic rule of thumb has been that the private lives of public figures become news when they affect their work or when they evolve into legal proceedings. A homosexual female athlete may not be news, but a world-famous female athlete who gets sued for "palimony" by another woman is. Sensational news, in fact.

Billie Jean King is not the first female athlete to have her sexual preferences questioned. Martina Navratilova's relationship with another woman was the topic of lurid headlines in the scandal-loving British press during Wimbledon last year. Later, her poor performance would be blamed, in part, on the hounding she took at the hands of the British press. Billie Jean King was there for that and she must have thought about it when she pondered how to handle the suit filed against her. "I expected the absolute worst," she told The Washington Post's Barry Lorge the day after her press conference, "and . . . anything I got beyond that was fortunate."

Whatever she gets beyond that will be due in some measure to the way she has handled the situation so far. While she initially responded to the suit by denying the allegations, she quickly reversed herself and, against the advice of her attorney, acknowledged the affair. She said she thought it was important to be honest with the public.

Unlike members of Congress who have been caught in sexual or financial wrongdoings, Billie Jean King did not try to weasel out of her problem by blaming alcoholism or temporary insanity. Nor did she get sanctimonious about the whole thing, the Way Paula Parkinson's friend, Rep. Thomas B. Evans (R-Del.) did. Without ever responding to Parkinson's allegations that she had a long affair with him, Evans issued a statement regretting any "association" with her and asking "my family and the Lord to forgive me."

Joe Hinson, the conservative Mississippi congressman who was charged with committing sodomy in the Longworth House Office Building, confronted his problem by blaming it on "dissociative reaction" caused by "intense emotional and physical exertion" of his work. While "dissociative reaction" may be a useful psychiatric term, it's also a politically useful term for dissociating yourself from what you have done wrong. It wasn't the real you that got caught -- it was some temporarily insane person, some temporarily alcoholic person, yet another member of the devil-made-me-do-it school of self-reliance.

King has said the reaction to her confession has so far been "fantastic." An exception was Mike Lupica, a sports columnist for the New York Daily News, who opted for the cheap-shot analysis of the way King has handled her problem." . . . When she told the press in Los Angeles Friday that she was 'speaking from the heart' -- which she seemed to be -- she was also speaking from the wallet," he wrote.

"What she was doing was making a very sound decision, from an economic standpoint, from a professional standpoint, certainly from any public-relations angle you can think of," Lupica wrote. "Billie Jean has always been a very smart woman when it has come to her own career." Sinister through Lupica tries to make that sound, there is nothing wrong with being smart when it comes to your own career. Even if you are a woman. And presumably King thought about the public relations aspects of her announcement. Had she not, she would have been foolish.

Billie Jean King is the first female athlete to publicly acknowledge a homosexual liaison. There will surely be others, just as there have been homosexual congressmen and congressmen who have gotten caught in extramarital heterosexual affairs. But King has emerged from this better than the others., and has offered an object lesson for others to follow: Tell the truth.