"[I won]," the 23-year-old captioned a slideshow of her and Marroquin looking cozy in a matching dress and blazer.
Marroquin and Lowry were married for four years before filing for divorce. The two share 3-year-old son Lincoln, and have previously had a decent co-parenting relationship despite the cheating accusations on both sides that led to their divorce.
Lowry, who has a new partner herself, was not having her castmate's diss, responding in a not-so-subtle way on Twitter.
First, she posted a string of the crying laughing emojis, which fans immediately picked up on as being a response to DeJesus.
???— Kail Lowry (@KailLowry) December 3, 2017
Lmaooooo y’all picking up What I’m laying down i see— Kail Lowry (@KailLowry) December 3, 2017
"[Laugh my a-- off] y'all picking up What I'm laying down i see," she tweeted, before dealing a crushing blow.
#iwon more time with my son ?— Kail Lowry (@KailLowry) December 3, 2017
"[I won] more time with my son," she wrote.
After this backlash for her caption, DeJesus changed it to a simple heart emoji.
This isn't the first time DeJesus has lashed out at Lowry on social media. Last month, she went nuclear, posting a text message exchange between Marroquin and Lowry on Twitter before wiping her social media account clean.
DeJesus and Marroquin confirmed they were dating in October after the filming of the Teen Mom 2 reunion, but have been spending time together for months before that.
"It's amazing with Bri and me," Marroquin told Radar Online shortly after the couple confirmed they were dating.