6:44 AM PT -- 10/12 -- TMZ Sports has learned Chuck's wife, Heidi, is also in some hot water following the alleged incident early Monday morning.
Law enforcement sources tell us Heidi was cited on the scene because police could not determine the aggressor.
As Chuck said in the statement he released yesterday, the UFC legend asked cops if Heidi could remain at their house with a minor child who was on the premises, while he was taken to jail.
Police obliged ... and Chuck was locked up for several hours in an L.A. jail.
As for what happened before and during the incident, we're told Chuck and Heidi were at a party. They returned home and got into an argument that allegedly turned physical.
We're told neither party had injuries.
4:16 PM PT -- Liddell is opening up on his arrest ... saying he was the victim and claiming his wife had assaulted him, causing bruises and lacerations.
Although Liddell says he never got physical with his wife, he claims he was told she would be arrested, so he volunteered to go to jail in her place.
"This was one of the many times I have tried to shield a family mental health issue from the public purview," Liddell said in a statement. "It has become painfully apparent that this cannot continue, as our private life has now reached a public breaking point."
10:46 AM PT -- Liddell was just released from jail in L.A. ... and all things considered, appeared to be in good spirits as he left the Lost Hills sheriff's department.
Chuck didn't speak with reporters as he hopped into a Mercedes-Benz and rode off ... but acknowledged their questions with a fist pump.
Chuck Liddell was arrested early Monday morning for domestic violence ... and the UFC legend is currently sitting in a Los Angeles jail cell.
TMZ Sports has learned the L.A. Sherriff's Department received a call about a fight at a Liddell's Hidden Hills home. When cops arrived, they investigated ... and determined the 51-year-old former fighter was involved in a verbal argument that turned physical.
We're told the alleged victim is Liddell's wife. She did not require medical attention.
Chuck was taken to jail ... where bail was set at $20,000. He's listed at 6'2" and 240 pounds on his booking sheet.