A 55-year-old Oxon Hill woman won an $82,000 breach-of-promise suit yesterday against a former live-in lover she testified took her to ecstasy and to Spain but not to the altar. A four-woman, two-man jury in U.S. District Court made the award to Dorothy Dozier, an investigator for the federal Equal Employment Opportunity Commission who said she was promised more than she got from Casper B. Duff Jr., 53, between 1972 and 1977.

The suit was brought under a now-defunct breach-of-promise-to-marry statute, outlawed by the D.C. City Council April 7, 1977. Dozier's suit, filed nine days before the old law's demise, is believed to be the last such lawsuit filed in the District.

Dozier testified this week before Judge Peter H. Wolf that she and Duff, an oceanographer with the federal government and a resident of Louisiana, were introduced by a mutual friend in 1972 when they were both married.

She testified that the two fell in love immediately and agreed to marry as soon as they could be properly divorced.

While they waited for final divorce decrees, Dozier testified, she and Duff "became very close friends and did a lot of exciting things together."

She said she traveled with Duff to Barcelona, Spain, on a two-week trip, that they lived together at her home and shared a very active sex life.

Dozier said that in 1974 she and Duff made plans to purchase a 14 room house near the Potomac River in Oxon Hill. They were to be co-owners of the house, she said which would serve as their home when they were married. Duff was to pay $10,000 as his share of the down payment, but never came up with the money, Dozier testified. Dozier said she borrowed $10,000 from a friend in order to purchase the house.

Duff testified that he never promised to marry Dozier and never, in fact, even discussed being married.

"We had agreed to just enjoy each other's companionship and have a good time," he testified.

He said he quickly dismissed the idea of marriage when Dozier brought it up on one occasion in 1974.

"She spent a lot of money of expensive clothes and furniture. she had expensive tastes in everything," Duff testified. "She had me to go over her books in 1974 and things were a mess. She could hardly keep up her furniture payment. I told her I didn't know how she made it."

At that point Duff testified that Dozier suggested the two be married. "I told her I had enough financial problems of my own and that I was in no financial condition to marry her."

Dozier's attorney, Harry T. Alexander, described her in closing arguments as "a poor gullible woman who believed this scoundrel's promises that he would marry her."

"When my client ran out of money and couldn't give him any more, he ran out on her and went back to his former wife," Alexander told the jury.

Alexander Benton, Duff's attorney, argued to the jury that Dozier was "a mature, urbane and sophisticated lady" who had been through two marriages and divorces and was not misled by his client.

"My client was not a rich man, but he was fairly comfortable when he met Mrs. Dozier," Benton argued. "My client was receiving income from his real estate properties. She knew about his income and wanted to take advantage of him."

The jury, however, did not agree. It awarded Dozier $12,000 for a breach of promise to marry and another $70,000 for fraudulent misrepresentations she said were made by Duff, including his gift to her of a $1,500 ring bearing a pear-shaped, multi-carat diamond.

The last previous breach-of-promise suit in the District was heard in 1971.