Northern Virginia Del. Dave Englin will retire from politics after admitting to an extramarital affair Monday night.

The Washington Post first reported late Monday that Englin, D-Alexandria, met with local Democrats to tell them of his intentions not to seek a fifth term and instead would focus on his relationship with his wife and son. During that meeting, he admitted to cheating on his wife, the Post reported.

Englin, 37, is co-founder of the Progressive Caucus and one of the most outspoken liberal Democrats in the Virginia General Assembly. He was a frequent opponent of House Republicans during the contentious session in which a slew of conservative social legislation passed the GOP-controlled legislature.

“On behalf of the House Democratic Caucus, I want to thank Del. Englin for his years of dedicated service in the General Assembly,” said Del. Mark Sickles, D- Franconia, chairman of the House Democratic Caucus.

“He has been a tireless advocate for his constituents and for the equality of each and every Virginian. During his tenure in office, he has worked to end discrimination in all forms, and against all people without regard to race, gender, ethnicity, religion or sexual orientation.”