On a rewatch, I found it really crazy how much this dysfunctional relationship––which initially seemed to be nothing more than a b-plot about infidelity and a reversal of traditional marriage dynamics––has sneakily grown into the primary driver of events in the plot. And it started way before the S3 betrayal.
Many cite the beach scene from the S2 finale as one of the most emotionally cathartic scenes in the show. And I totally agree––its fire. BUT, I also think its larger story repercussions are often overlooked; especially how it basically caused the entire S3 civil war plot. Lets just run down the cause and effect:
1. When Tom finally stands up for himself, Shiv is sent into a bit of a guilt-spiral, confronted with just how awful she's been to him. She is reminded how much she NEEDS him, and that she has been taking his support for granted
2. The two main candidates for the sacrifice are Tom and Kendall. Logan says as much when he consults Shiv, and basically asks her to choose between them. If Tom hadn't shared his feelings with her MOMENTS before, she likely would have continued the objective/heartless mindset she showed towards him earlier in the episode. But, because her mistreatment of him is in the forefront of her mind, she decides to protect Tom. This could be read as a change of heart, but i think it's more accurate to say that she does it to make herself feel better; to mend her cognitive dissonance and affirm to herself that she IS a good person after all.
3. Her decision to protect Tom also serves as the final nail in the coffin for her succession aspirations. Logan says that this is the type of decision that she would need to be making if she were to replace him, and the way she frames it as "I cant choose" but also "please not Tom, for me" signifies a shift in the once-equal dynamic between her and Logan. He follows her wishes because he loves her/she's his favorite, and not because he respects her strategic opinions. I think this moment feeds into his complete lack of respect for her in S3.
4. Of course, Shiv's protection of Tom is what puts Kendall under the axe. I think it's clear that Kendall had no intention of going civil-war-mode before Logan deemed him as the sacrifice, and made the NRPI comment about the boy. Neither of these things would have happened without Tom dumping his emotions on Shiv
5. The beach confrontation is also what gives Tom more independence going into S3, tipping the relationship in his favor for a while until it's completely turned on its head in Italy.
I just think it's so cool that the seeds of an entire season's worth of story are sewn in one little scene of emotional confrontation. The Tom/Shiv dynamic has been just as impactful as the one between Logan and Kendall imo, and it's really exciting that the story has such unexpected engines of conflict––and that they all weave around each other in such beautiful ways.
Best show ever guys :,)