EXCLUSIVE

UFC fighter Rachael Ostovich has filed for a restraining order against her MMA fighter husband, Arnold Berdon, in the wake of a violent incident over the weekend ... TMZ Sports has learned.

Rachael filed for the order herself in Hawaii on Nov. 19 -- and based on court docs, it appears the order was temporarily granted and is set to stay in effect until May 18, 2019.

As we previously reported, Ostovich was hospitalized with a broken orbital bone along with other injuries after an incident in Hawaii.

Multiple sources tell us ... Ostovich is pointing the finger at Berdon and that's why she's filed the restraining order.

Cops have opened a felony domestic violence investigation but have not released the name of the suspect.

We spoke with a family member who is very close with Berdon, who tells us Arnold is seeking a lawyer and intends to defend himself against allegations he attacked his wife.

We're told Berdon will argue he was attacked first and defended himself.

Berdon is also a pro MMA fighter. He's 27 years old with a 7-2 record, according to Sherdog.com.

He's listed at 5'9" and 135 lbs. Berdon's last fight was back in June -- a unanimous decision victory over Jeremias Fernandez.