Artem Chigvintsev and Nikki Bella's Marriage Has Been Volatile

Artem Chigvintsev's domestic violence arrest didn't come out of left field, at least according to people who say they know him and Nikki Bella ... they tell us the relationship has always been "volatile."

Sources with direct knowledge tell TMZ … Artem and Nikki's close friends, including their former 'DWTS' cast and crew members, are not entirely shocked by Artem's claims Nikki threw shoes at him during a heated exchange.

We're told Artem and Nikki's marriage has been troubled for some time, and it wasn't exactly a secret to anyone in their orbit.

Given the history here, we're told the general reaction among Artem and Nikki's friends to his felony domestic violence arrest was this ... "Shocking but not shocking."

TMZ broke the stories ... Artem was busted Thursday morning for corporal injury to a spouse or cohabitant, and a radio dispatch call reveals Artem claimed Nikki threw shoes at him. Artem was the one who initially called for paramedics, before changing his mind and asking them not to come to their Napa Valley house.

Our sources say folks close to the couple were only aware of past verbal altercations between Artem and Nikki ... and no one had heard of any physical fights before Thursday's incident.

Still, we're told the consistent narrative from their marriage has been that their arguments often stemmed from issues involving control and belittlement.

Nikki's on the record saying their marriage needed work, particularly with communication ... back in 2021 she revealed she and Artem went to couples therapy because of how he spoke to her.

Our sources add ... Artem is not living in the Napa Valley house right now, and Nikki is watching their 4-year-old son Matteo.