Republican U.S. Rep. Tony Gonzales of Texas was forced into a primary runoff with his GOP opponent in Tuesday's vote as he faces calls to resign over allegations of having an affair with an aide.

Gonzales, who has said he won't step down, entered the nation's first big primary of 2026 under pressure from fellow House Republicans after published reports last month that alleged to show explicit text messages between him and the former staffer.

The three-term congressman now faces another rematch with GOP challenger Brandon Herrera, a gun manufacturer and YouTube gun-rights influencer who narrowly lost to Gonzales by less than 400 votes in the 2024 primary. Neither candidate secured more than 50% of the vote in the four-way primary election, setting up the May 26 runoff election.

President Donald Trump endorsed Gonzales in December, and last week, Gonzales was among the Texas Republicans in attendance for Trump's visit along the Texas coast.

“There will be opportunities for all of the details and facts to come out,” Gonzales said last week in Washington. “What you’ve seen is not all the facts.”

Gonzales, a father of six, first won his seat in 2020 after retiring from a 20-year career in the U.S. Navy that included time in Iraq and Afghanistan.

His win in 2020 beat back Democratic expectations in the sprawling district along the U.S. border with Mexico that stretches from western San Antonio to El Paso. His victory was fueled in part by Trump’s surprisingly strong performance in the heavily Hispanic Rio Grande Valley.

Gonzales said in a recent social media post that he was being blackmailed and then suggested in another post that he is the target of “coordinated political attacks.”

The San Antonio Express-News reported that it had obtained text messages in which the former staffer, Regina Ann Santos-Aviles, wrote to a colleague that she had an affair with Gonzales.

The Associated Press has not independently obtained copies of the messages. An attorney for Adrian Aviles, Santos-Aviles’ husband, has said the husband found out about the affair before his wife’s death.

Santos-Aviles, 35, died in September 2025 after setting herself on fire in the backyard of her Uvalde home. The Bexar County Medical Examiner’s Office later ruled her death a suicide.