Mark Lohman's job falls somewhere between marriage counselor and divorce lawyer. His title is family mediator. His task is to arrange "civilized separations" for couples who wish to end their marriages.

He differs from a lawyer in that he is not the advocate for one spouse; he is the abitrator between both. He does not try to convince husband and wife to stay together, as would a counselor, but rather to separate in such a way that causes them the least frustration, anger or bitterness.

"Too often when people separate, they want to put the whole mess in the hands of their lawyers and abdicate all responsibility for deciding to separate," said Lohman, who lives in Arlington. "Lawyers, by their nature, have to take sides, so the couples ends up with a long, drawn-out combative process in which one is trying to get more than the other."

With about 1 million divorces annually in the United States, Lohman's unusual job represents a growing trend toward alternative methods of ending marriages. The American Arbitration Association has requested Lohman to draw up a blueprint which the organization plans to use in setting up a service to arbitrate issues between separate couples. A family mediation service in Atlanta offers a "package deal" that includes a specified number of counseling hours and produces an informal agreement which can serve as the basis for a legal separation.

Self-help books on separation and divorce procedures are appearing in bookstores and counseling clinics dealing with legal and economic aspects of divorce are finding a growing clientele.

Lohman works out of his home at 2710 N. 25th St.

"Laying the groundwork for separation outside the legal arena can produce more flexible agreements, partly because the partners aren't dealing so much as adversaries, and partly because they can afford the time to work out terms more personally suited to them without running up astronomical legal fees," Lohman said.

His concern that couples design their own separation terms also is ethical."Marriage is a very personal decision, one sanctioned by society and one in which both partners take an active role in bringing it about," Lohman said. "The decision to separate is just as personal and one that should not be left to outsiders to negotiate. It also demands full participation."

For $25 an hour, Lohman will meet with each spouse separately, find out the issues provoking the separation, determine what each wants out of the separaton, decide with the couple how property will be divided and produce an informal agreement that can be translated into a formal contract by a lawyer.

"Usually, we'll reach the informal agreement within a month, after I meet with each partner about once a week," Lohman explained. "That comes to about $100 for each. A lawyer then would charge about $75 to make the agreement draft a formal contract."

Since the 34-year-old former sociology professor began his one-man mediation service in March, he has counseled about 30 couples, producing agreements that cover child care, how bill payments will be met, how taxes will be paid and how furniture and other property will be divided among other matters.

Lohman, who taught sociology at the University of California at Berkeley for three years, just abandoned a high-paying government job as education researcher for the National Institute of Education to begin his new career as a mediator last March.

He says the problems he countered inseparating from his own wife propelled him into mediating those of others.

"I was convinced I could do the job better than two lawyers hurtling their client's demands at each other through letters and phone calls," Lohman recalls. "My wife and I started separation proceedings in the fall of 1974. We finished the process last January. By the end of the ordeal, I realized I wasn't only married to my wife, but to her lawyer as well."

Lohman said fees for his wife's lawyer came to about $1,500 while fees to his lawyer totaled about $500.

"My wife relied on her lawyer for advice," Lohman says. "I consulted mine only to find out my legal rights - which is the proper role for a lawyer to begin with."

Some of Lohman's former clients make it sound as though separating was a pleasurable experience.

"When you have a lawyer, you're automatically pitted against your spouse, because you're out to win the case, rather than plan a calm transistion from married to single life," said one Reston woman who spent $210 and eight weeks negotiating a separation from her husband through Lohman. "I know, I went through a divorce before that cost me two years of pain and about $3,000. It makes a difficult situation much easier when you're negotiating through an intermediary rather than going to battle hoping your side is stronger."

Another Reston schoolteacher noted that Lohman advised her on financial matters and suggested ways to change her lifestyle so that she was "n longer dreading life as a single person."

Maybe Lohman clients like his results because he likes his work.

"You know, sometimes people spend their whole lives looking for work that suits all aspects of their personalities," Lohman reflects. "This is me. I love working with people, but I'm no psychologist. I'm action-oriented and I think people like that when they're looking for a quick settlement. I'm not the kind to just listen to somebody's troubles every week: if they want an equitable agreement, then that's what I'll get them."

But after having set in motion what might become a highly popular service for separating couples and finally breaking even financially with his new practice. Lohman doesn't plan to make mediatin any more his career than were his stints as university professor and bureaucrat.

"I've got this file of ideas, see. I want to finish developing these children's educational games I've been working on, and I've been thinking about trying to set up child care facilities in shopping centers so mother doesn't have to get a babysitter everytime she has to run an errand. But for right now, solving problems is right up my line."