"Castle" is dealing with a pretty major split. No, not the one between the main characters, Rick Castle (Nathan Fillion) and Kate Beckett (Stana Katic); the one between the ABC series and its fans. The ratings for the latest episodes of the long-running show are in, and they suggest viewers may be tiring of the unexpected return to "will they or won't they?" status for Castle and Beckett in Season 8. 

Monday's episode, "The Nose," earned just a 1.1 rating (signifying the percent of U.S. households tuning in) in the key 18-49 demographic -- good for 6.94 million viewers. That matches the number for the previous week's episode, which also happens to be the lowest the series has received in eight seasons.  

In episode 2 of "Castle" Season 8, Beckett asked Castle for some space to sort out some things in her life – namely, solving her mother’s murder and breaking up a dangerous drug ring. The news came as a shock to loyal viewers who only just got to see the couple tie the knot in Season 7 after years of waiting. 

Nathan Fillion appeared on "Jimmy Kimmel Live" on Oct. 14, with the host jokingly accusing the actor and the show of dealing fans a low blow with their sudden split. 

“It seems weird and almost abusive,” Jimmy Kimmel chided. “How do your fans react to it? They don’t like it, right?”'

Fillion responded by mimicking his fans’ most common reaction: “What??!”

Later, Kimmel playfully accused the show’s twist of being traumatic for fans.

“You would think it would drum up all sorts of negative emotions based on when you were a kid and your parents split up, in a way,” Kimmel said.

“No,” responded a sarcastic Fillion, with a wink to the crowd. “Not at all.”

Fillion can joke -- and who doesn't appreciate some Fillion sass? -- but fans don't seem to be laughing along with him. 

Maybe the Castle/Beckett split isn't the only reason for the decline in ratings. For one, after eight seasons the show might have been destined to be experiencing fan fatigue no matter what plotline the writers chose to take on this year. In fact, the Season 8 premiere debuted to just a 1.2 rating before fans even knew about the breakup. Many viewers might have checked out towards the end of Season 7 when contract issues cast doubt on the future of the series. Plus, heavy competition on Mondays between "Monday Night Football," "NCIS: Los Angeles," and "Blindspot" might be forcing fans to watch online or On Demand days later, skewing the show's ratings lower.

However, one need only peruse social media for a few minutes to discover that many of the fans who are watching do not appreciate the show's decision to separate the couple, marginalizing Fillion and Katic's romantic chemistry, which has carried the show for years, to just a few scenes per episode.

In Monday's "The Nose," Castle's partner, crime-sniffing witness Mia Laszlo (guest star Stephnie Weir), told him it was just a matter of time before Beckett came around. 

“Beckett still loves you,” Mia said. “What you and Beckett have, now that’s the genuine article.”

Hopefully the "Castle" producers get the message sooner rather than later, because fixing the marriage might be necessary to fix the show. 

"Castle" airs Mondays at 10 p.m. EDT on ABC. Watch Mia give Castle a dose of optimism in a tear-jerker moment from Season 8, episode 5 below: