Sean Parnell, a leading Republican candidate for Senate from Pennsylvania, suspended his campaign on Monday after a judge ruled that his estranged wife should get primary custody of their three children in a case in which she accused him of spousal and child abuse.

Mr. Parnell, who was endorsed by former President Donald J. Trump in September, said he was “devastated” by the decision and planned to appeal.

“There is nothing more important to me than my children, and while I plan to ask the court to reconsider, I can’t continue with a Senate campaign,” he said in a statement. “My focus right now is 100% on my children, and I want them to know I do not have any other priorities and will never stop fighting for them.”

Mr. Parnell’s estranged wife, Laurie Snell, testified in court this month that Mr. Parnell had repeatedly abused her and their children, choking her and hitting one of their children so hard that he left a welt on the child’s back. The Butler County judge wrote that he found Ms. Snell to be “the more credible witness” and that he believed Mr. Parnell had committed “some acts of abuse in the past,” according to The Inquirer.

The Pennsylvania seat, currently held by Senator Pat Toomey, a Republican, is widely considered one of the most competitive Senate races in 2022.