A husband who admitted killing his wife after finding her in bed with another man was sentenced to 18 months in prison by a judge who said that such a killing was understandable.

The defendant, Kenneth Peacock, 36, said he killed his wife, Sandra, 31, last Feb. 9 with a single shot to the head from a hunting rifle a few hours after he had arrived home unexpectedly during a storm. Mrs. Peacock's lover escaped unharmed.

In handing down the sentence on Monday, Judge Robert E. Cahill of Circuit Court said he was reluctant to give any prison time to Mr. Peacock, who had pleaded guilty to voluntary manslaughter.

"I seriously wonder how many men married five, four years would have the strength to walk away without inflicting some corporal punishment," Judge Cahill said.