"Seeking Sister Wife" star Dimitri Snowden could be in hot water ... 'cause one of the women on the show is accusing him of domestic abuse ... according to new legal docs.

Christeline Petersen filed a restraining order against Dimitri claiming he's been physically abusive during their relationship over the last year ... to the point it's even scared her 2 young daughters.

In docs, obtained by TMZ, Christeline says back in January she was woken up one day by him "slamming my head into the headboard of the bed and he was yelling at me." She went on to claim Dimitri slammed her head on the headboard several times. She says she filed a police report.

What's more ... she claims Dimitri was abusive during sex. She says "he choked me during sex, even though I told him not to." She added, "The more I struggled the more he enjoyed it." Christeline says her only choice was to go along with it.

She claims, "I stopped saying no after a few times, because any struggle by me would prolong the sex and choking." Christeline claims things got so out of hand one time she got very dizzy and felt like she was going to pass out. She says she suffered bruises, scratches and redness around her neck from the alleged attack.

Christeline, who came to the U.S. from South Africa to be courted as a third wife on the TLC reality show, beelined it to court and the judge granted her a restraining order. Dimitri must stay at least 100 yards away from her and her 2 daughters because she says they are afraid of him "as he often yells and punches the walls or furniture."

We've reached out to Dimitri and TLC, so far no word back.