Shauna, Jeff, and Callie
Season three emphasizes a significant family bond by showing how Shauna's actions have begun to result in Callie and Jeff pushing themselves further away from Shauna, even though they both show signs of wanting to help Shauna and better understand her. Without Shauna letting them in, they begin to rely more heavily on each other as Callie and Jeff start to come to the understanding that, in Shauna's growing unhinged state, she may not be the safest person to be around. However, season three does poke a few holes in Jeff's claims about reading Shauna's journals, or it at least questions how much about the Wilderness in the later months was actually described. Meanwhile, Callie's desperate attempt to understand where Shauna's hesitation toward her comes from results in a particularly violent ending.
While Shauna runs around with Misty, Taissa, and Van trying to determine where the tape from the Wilderness came from, Callie and Jeff are left in the dark as to what Shauna is doing and what makes this tape so significant. However, Jeff is not nearly as innocent as he claims to be, or feels like he is. Jeff blackmailed the Yellowjackets in an attempt to make back money due to his failing furniture business. His blackmail scheme, using the Wilderness symbol against the Yellowjackets, is not only a breach of trust given it confirms that Jeff read Shauna's journals, but also shows that either Jeff knew the full truth and did not care, or did not know nearly as much as he believed he did, and still was willing to use the survivors' most traumatizing times of their lives as a way to bait them out of money. Jeff may want to see himself as a caring and loving husband, but he lacks the trauma that the narrative uses to justify and explain the actions that the survivors take of their own free will as adults.
Ultimately, what also ends up being the final straw for Callie is hearing Lottie's answer when Callie asks if Shauna loves her. Callie and Shauna have always had an estranged relationship, and even in moments where they get closer, Shauna still refuses to fully let her daughter in or allow herself to truly love Callie freely. Lottie's explanation is much darker than that Shauna was just traumatized from losing her baby boy in the Wilderness. Lottie suggests that Shauna is jealous of Callie, potentially for the reason that Callie is not only more than Shauna was at the same age before the plane crashed, but also because Callie is very similar to Jackie. The idea that Callie could be similar to Shauna terrifies Callie, given what she knows Shauna is capable of. However, there is a chance Lottie could have walked away had she not continued, suggesting Callie as the child of the Wilderness and the daughter of all the survivors. Callie's final interaction with Lottie is very overwhelming, especially for someone who did not know what to expect from how far Lottie had gone down the rabbit hole of creating the Wilderness religion.
After revealing herself to be responsible for Lottie's death to Jeff, Callie and Jeff pack up and move out of the house, deciding that they need space from Shauna. But, while Shauna may be upset that Jeff and Callie have left, it also opens an opportunity for Shauna to return to the freeing feelings and acts of her Wilderness counterpart, who was never more alive than when the survivors were out hunting and fighting for their lives. This is Shauna's opportunity, in a way, to finally live her life for herself without having to feel confined to the role of stay-at-home mother she has found herself living.