Artem Chigvintsev and Nikki Bella are about to start a new chapter in their lives ...

because we've learned they've settled their divorce. According to new legal docs, obtained by TMZ, Artem and Nikki went to mediation earlier this month and hammered out a divorce settlement. Our sources tell us Artem and Nikki decided to quickly settle their divorce because they both want to move on, in part because it was getting very expensive to pay lawyers .

.. plus the whole process was becoming emotionally draining.

We're told Artem and Nikki aren't exactly getting along these days ...

but they are cooperating with one another and their relationship is very much a work in progress. A rep for Nikki tells TMZ ..

. "Nikki’s number one priority has always been her son and privacy on the matter. She is thankful for all of the love and support she has received during this difficult time.

" The terms of the settlement are unclear ...

but as we first reported, a judge already ordered Artem and Nikki to share custody of their 4-year-old son, Matteo . Artem was seeking spousal support from Nikki, but in her divorce filing she checked the box to block the court's ability to award spousal support ..

. so it will be interesting to see how their settlement addresses spousal support. The divorce filings came in the wake of Artem's domestic violence arrest back in August .

.. though prosecutors ultimately decided not to file criminal charges against him.

Artem and Nikki also had restraining orders agains.