Family life vs. public life - the officeholder's dilemma.

THE Washington grapevine has always been ripe with stories of family life gone sour amid the tanglings, trappings, and time constraints of government life.

Both David R. Gergen, who resigned Jan. 15 as President Reagan's director of communications, and former chief congressional lobbyist Kenneth M. Duberstein, who had resigned Dec. 15, cite the encroachment of job demands on personal and family life as a significant factor in their decision to leave government service. The experiences of their families can serve as a convenient barometer of what is happening to families all across the country whose main breadwinners are in high-pressure, time-consuming executive or political jobs.

''What is happening with families in Washington is merely a reflection of what is happening to them all over this country,'' says Prof. Gerda McCahan of Furman University, a family research expert. Economic pressures and social change are widely redefining relationships and reordering the priorities of family life, she says.

As President Reagan's chief congressional lobbyist, Mr. Duberstein helped forge bipartisan accords on the 1982 tax increase, the 1983 revision of the social security system, the MX missile, and authorization of American troops in Lebanon. Such mega-tasks put predictable strain on the microcosm of family life.

''I used to get home from the White House anywhere from 9:30 to 12 o'clock (at night). Sydney (his wife) can tell you that one of the ways she always knew I was on my way home was the signal line (phone from the White House) started ringing,'' Mr. Duberstein says. He recalls a visit with his wife's parents. ''We pulled up to her folks' house in Philadelphia. . . . Her mother came out of the door laughing because the White House had already called three times with messages.''

Sydney Duberstein has her reminiscences, too: ''We'd be alone even on social occasions. We would stand together for a few minutes during the cocktail hour. We would have dinner at separate tables. We'd be driven back to the White House in a White House car, get in separate cars, and drive home.''

Unlike many Washington political couples, the Dubersteins knew what they were in for before they got married. They had no illusions about the ''glamour'' of working in the White House, and they knew, in Mrs. Duberstein's words, ''that it wouldn't be a career forever.''

She holds a full-time job in the General Services Administration and says she never felt shunted aside by the pace of her husband's high-powered position. But she observes that ''obviously his job was more important than mine, and his schedules did dictate a lot of things.''

The Dubersteins tried to see his daughter, Jennifer, ''late Saturday afternoons through Sunday as many weekends as possible.'' He kept a drawer of crayons and coloring books in his White House office to entertain her when she visited him at work on Sunday afternoons.

Mr. Duberstein now has a lobbying job with the firm of Timmons & Co., and his wife says she feels a vast difference already: ''We can talk in full sentences now without the phone ringing.''

David Gergen, who is now a fellow at the Kennedy Institute of Politics at Harvard University, rules out a husband-wife interview.

''Privacy is one of the last things my wife still has (after the strains of Washington), and she wants to hold on to it,'' Mr. Gergen explained as I talked with him here.

On their 16th wedding anniversary last year, he told his wife, Anne, he'd be leaving the administration. She cried for joy. The year before, his two children - now 10 and 13 - drew him a picture for Christmas. It showed what would happen if he stayed at work in the White House: bald from tearing out his hair, baggy eyes, and no muscles.

''If there's a problem in government, (it is that) you never have enough time ,'' Mr. Gergen says in a soft, unrushed tone that shows his years of polish in the communications field. ''It's easier to lose touch with your friends and to start closing up as an individual, saying, 'I can't deal with that. I simply don't have time for it.' ''

Mr. Gergen is quick to point out that many couples overcome the negative side of life in Washington - time pressures, trappings of status, social obligations - and have stronger marriages as a result. He observes that former Speaker of the House John W. McCormack, for instance, said no to all the party invitations, spent every evening with his wife at home, and ''they had a wonderful relationship.''

But he hastens to add that for a family close to the heartbeat of government, ''the greater the dangers'' - the threats to family life - ''the greater the rewards. You do have a window on the world here. And it's a wonderful town for children in that sense - the chance to see a real president, or to see a real queen, or to see a real leader from another nation.''

He explains the part family considerations played in his decision to resign. ''I think part of what one always needs to remember is that the family does pay a lot of the price and shares in very little of the glory. The individual who's working in the White House tends to get the attention, and not the family. And that's tough.''

Another thing that's tough, says Mr. Gergen, is helping children understand the transitory nature of power in the capital.

''You have to be very aware that it is not you, the all-powerful person - it's the title, it's the office. It's hard for children sometimes to see that. They like to think of their dads, or their mothers, as holding these fancy titles, whether it be in Congress or whatever, and they sort of see them in terms of their public persona. You really need to get to know them as private individuals, because that's the relationship that's going to count, that's going to matter over the years.''

White House worker Kathy Reid has known Mr. Gergen since working with him in the Nixon administration. ''It's obvious when you see him with his children that they think he's the greatest thing on earth,'' she says. ''He's proof that you can work the way he does and still have a relationship with your family. But you must have a wife who's willing to hold the household together, call the plumber, and pay the bills. She (Anne Gergen) accepted that and understood it and handled it.''

''I think there is a time to leave and to begin rebuilding,'' says Mr. Gergen , speaking of his relationship with his family. ''We've had some difficult moments, some very difficult moments in the last few years. But we've had some very good times, too, and I like to savor the good moments.''