A Montgomery County Circuit Court jury last night convicted a Gaithersburg man of forcing his wife to commit sexual acts with him against her will in one of the first contested cases under Maryland's new spousal rape law.

The 27-year-old man, whose name is being withheld to protect the woman's identity, was found guilty of two counts of a second-degree sexual offense and one of battery. He was acquitted of more serious charges -- two counts of first-degree sexual offense, punishable by life in prison.

The jury deadlocked on a sixth count involving alleged "unnatural or perverted" sex acts. The prosecution dropped that charge after the verdict was rendered.

The man, who could be imprisoned up to 40 years, remains free on bond pending sentencing Nov. 30.

The jury deliberated nine hours in a case that opened up the couple's private life to public scrutiny. The three-day trial before Judge DeLawrence Beard was among the first in Maryland under a state law that took effect in July 1989. The statute removed marriage as a defense when a spouse is charged with sexually assaulting a partner.

The man had pleaded guilty in September 1989 to battery and was later sentenced to 18 months in jail. But he challenged the conviction, saying his plea had not been voluntary, and it was overturned in April. The man was then charged with the offenses that came to trial this week.

The couple married in 1987. The woman testified the marriage began to deteriorate in late 1988.

The 23-year-old woman testified that her husband awakened her about 2 a.m. on Feb. 17, 1989, and demanded sex. The woman, a nurse, said when she refused to engage in the act he wanted, he put a pillow over her face to muffle her screams and used a sexual device on her. The woman said she was assaulted until 5 a.m.

A physician who examined the woman said she was injured by the assault. The woman testified she then left their apartment with her 3-year-old son, and that she waited five days to file charges because she was unaware of her legal rights. "It had crossed my mind, but I was told it was a husband and wife thing," she testified.

In closing arguments, defense attorney Francine Taylor attacked the woman's credibility, saying her allegations were made in anticipation of divorce and child custody proceedings.

Prosecutor Barry Hamilton said the woman tried unsuccessfully to resist her husband's assault. "She did not want any part of what happened that night," he said. Hamilton said the defendant told the woman "that she did not have the right to resist. She was his property, his chattel."

In September, a Howard County man became the first person convicted under Maryland's spousal assault law when he pleaded guilty to two assaults on his estranged wife. In that case, the man was charged with raping his wife at knifepoint and choking her with his hands.

Some domestic violence counselors in the Washington area say the incidence of marital rape is increasing, although many married women still are reluctant to report cases because of fear and embarrassment.

According to a recent study, one of every seven married women will be raped by her spouse at some time during their marriage, said Denise Synder, executive director of the D.C. Rape Crisis Center. A director at a battered spouse shelter in Baltimore said 30 percent of the women seeking legal help report sexual abuse by a husband as part of a pattern of domestic violence.

Virginia passed a marital rape law in 1986. The District has no specific law on the subject.