Are drugs behind the early Monday morning arrest of former UFC champion Tito Ortiz, who now faces domestic violence charges for assaulting porn queen Jenna Jameson?

The martial arts star claims his ex-porn star girlfriend of four years is addicted to the powerful prescription painkiller OxyContin, and he blames Jenna’s continued drug use for his arrest inside the couple’s Huntington Beach, California home on charges of suspicion of domestic violence on Monday.

Ortiz and his lawyer Chris Matthews accuse Jameson of drug addiction and claimed Ortiz never struck her.

“Jenna Jameson has been fighting an ugly battle with an addiction to Oxycontin for well over a year, and this morning, she had a relapse,” lawyer Chip Matthews said. “We’re here because Tito was trying to help her. Tito Ortiz never laid a hand on Jenna.”

Matthews claims Tito, the 35-year-old son of recovering addicts himself, found drugs in their home Monday morning, leading to the confrontation that ended with his arrest. Matthews also claimed the 36-year-old Jameson has made 911 calls threatening suicide over the past year.

Jenna gave birth to the couple’s twin sons, Jesse and Journey, in March 2009.