In a confrontation on a rural Petaluma roadway Monday afternoon, a Sonoma man was stabbed after assaulting his wife and her boyfriend, according to the Sonoma County Sheriff’s Office Tuesday.

Suspect Francisco Reyes, 38, was driving on Adobe Road about 2 p.m. when he spotted a passing car driven by his wife with her boyfriend in the passenger seat, a sheriff’s official said.

Reyes turned around and got in front of the other car, forcing it to stop near Hamilton Road, southeast of Petaluma. The altercation included Reyes confronting and grabbing his wife and repeatedly punching the boyfriend, who tripped on a curb and fell to the ground, the Sheriff’s Office said.

While under assault, the boyfriend, who wasn’t identified, pulled out a pocketknife and stabbed Reyes once, ending the fight, according to the report.

Reyes was taken to Santa Rosa Memorial Hospital for treatment, and then booked into the Sonoma County Jail on suspicion of misdemeanor domestic violence and false imprisonment, according to jail records. He remained in custody Tuesday in lieu of $30,000 bail.

The other man, who wasn’t identified, went to Petaluma Valley Hospital for a dislocated ankle. Deputies did not arrest the boyfriend, saying he acted in self-defense, the official said.