Christine M. Moore is challenging the presumption that all's fair in love.

In the halcyon days of her romance with former live-in boyfriend Miles Benson, she charges in a lawsuit in Fairfax Circuit Court, he promised to support her and provide her with a place to live.

In December, Benson "abruptly and precipitously" married someone else while Moore was vacationing in Florida, the suit alleges. When she returned, she found herself turned out of the Falls Church home they had shared, court papers say.

This week, in what attorneys say may be the first such case in Virginia, Moore, 35, sued Benson for $12,500 -- the amount she claims she lost by believing Benson's "vows of love and affection."

"I guess you could say it's unique," said Moore's attorney, Karl G. Sorg. "I have researched the case law . . . and this seems to be unique."

And some lawyers were skeptical about such a suit's chance for success in the Virginia courts, especially since until recently it has been illegal in Virginia for unmarried members of the opposite sex to live together.

"I've thought about this a lot," said Betty Thompson, a prominent Northern Virginia divorce lawyer. "I've never come up with a way I thought this sort of case could be successfully filed."

Moore could not be reached yesterday, and Benson, a reporter for the Newhouse National News Service, declined to comment, saying he had not seen the suit. He refused to confirm that he even knew Moore.

Benson's attorney, Gail Ross, said she had not yet seen the suit, but said, "I don't think the courts are going to be very sympathetic to it."

Specifically, Moore charges that she lost money when she gave up a lease to move in with Benson; she lost the use of her personal belongings when she had to leave the house they shared, and she did not take advantage of certain job opportunities because she was relying on Benson's promise to support her.

"We're not asking for alimony or palimony or support," Sorg said. Palimony is ongoing damages or support payments from someone a person has lived with but has not been married to. Sorg said the suit asked only for damages resulting from the fact that Moore changed her living circumstances because she believed Benson's promises.

Sorg admitted that given Virginia law and the attitude of the Virginia courts, "if this were a palimony case it would die aborning."

And Sorg said he realizes that if he and his client are successful, romance in Virginia may no longer include those wonderful promises and dreams whispered in the ear of one's beloved while courting.

"I think it would certainly have a somewhat chilling effect on those relationships," he said.