While very few expected the relationships developed on the A&E reality show "Married at First Sight" to last, things took a somewhat darker turn for former couple Ryan De Nino and Jessica Castro.

When the series came to a close last week, it appeared that Castro and De Nino had worked out some of their troubles that had led to rather aggressive arguments during the course of the show. They were one of the two couples who decided to stay married.

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However, on Saturday, De Nino took to Instagram to post a photo of a restraining order that Castro had taken out against him.

De Nino posted a response in the caption to the photo, in which he sounded angry but determined and brushed off the order of protection, implying that it was just an attack by Castro on his character.

"Bash me all you want, say whatever it is about me just remember this board don't break for nada," De Nino wrote, ominously adding, "Why I posted this will be thoroughly explained when the times right. #CheckMate."

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Meanwhile, Castro took to Instagram as well, where she posted her own vague message of determination.

According to rumors posted to "Married at First Sight" online fan forums, some are claiming that Di Nino stormed out of the taping of the show's reunion episode due to Castro allegedly accusing Di Nino of drug use.

Kinetic Content, the production company behind "Married at First Sight," released a statement to ET regarding the behind-the-scenes drama.

"We don't know all the details and can't comment on the specifics," the statement read. "What we can say is that unfortunately, couples on the show can go through real divorces, and divorce can often be difficult."

Kinetic Content also addressed the manner in which the contestants were chosen, stating, "The experts on our show have the best of intentions and highest hopes for success for each couple. After undergoing extensive background and psychological checks by third parties, couples agree to be legally married on our show. We document their journey for six weeks after their wedding, but we can't control how they behave, or govern their actions after production."

WATCH: Inside the 'Grueling' Casting Process for 'Married at First Sight'

"Our thoughts are with these individuals," Kinetic Content concluded in their statement. "As always we have offered each of them significant aftercare resources. We wish them nothing but the best, and hope they have a bright future ahead of them."

This was the second season of "Married at First Sight." The first season aired on the FYI network and ended up being a surprise hit. The show was moved to A&E for the second season in an attempt to reach a wider audience.