'This Is Us' season 1 episode 14 spoilers: New love triangle emerges; Chrissy Metz speaks on Kate's decision to join therapy group

The Pearson siblings face new struggles on the upcoming episode of NBC's breakout drama, "This Is Us" season 1.

Titled "I Call Marriage," the show's next episode will highlight the characters' complicated relationships. According to the official synopsis, Toby (Chris Sullivan) throws a wrench in Kate's (Chrissy Metz) journey to lose weight. Kevin (Justin Hartley) examines his previous relationships, while Randall (Sterling K. Brown) finds it difficult to accept his father's deteriorating health due to his illness.

In the storyline set in the past, Miguel (Jon Huertas) and Shelly (Wynn Everett) deliver some heartbreaking news to Jack (Milo Ventimiglia) and Rebecca (Mandy Moore), making them worry about their own relationship as a married couple. Also, Rebecca is excited when she receives an amazing work opportunity.

NBC released a new promo clip for the episode, and it shows the time when Jack and Rebecca got married. The teaser also features Randall having a discussion with his wife about the health of his father. At the end of the video, Toby visits Kate at the camp she's staying in where he meets Duke (Adam Bartley). The new character cheerfully approaches Toby and introduces himself, but Kate's boyfriend doesn't seem too happy to meet him. The preview hints that Toby, Kate, and Duke will be the new love triangle in the story.

Metz spoke with TV Guide recently, and she shared that Kate's decision to join a therapy group will affect her in a major way. "There are people that introduced to her at the camp who are a little bit of a devil on the shoulder and also a mirror," she said. "She starts to contemplate very different things that she's never had to before...There's a lot going on. There's been a lot happening. Sometimes relationships when they are tried and tested, they either fall apart or they get stronger. We don't know what's going to happen with that," she went on to say.

The first season of "This Is Us" airs every Tuesday night at 9 p.m. ET on NBC. The series is currently on a one-week break and will return on Feb. 7.