Over the course of Catastrophe, Sharon and Rob have developed a deep, multifaceted relationship. But it's important to remember that their relationship was born of casual sex, and nurtured by lots and lots (and lots) of increasingly less-casual sex. Even after a marriage, two kids, and who knows how many marital boinks, Sharon is still listed in Rob's iPhone as "Sharon London Sex." Just days (or hours?) before Muireann's birth, they were having a fairly vigorous and borderline-kinky quickie. Given that context, a two-and-a-half-month drought is a huge deal, and the dreaded postnatal dry spell informs most of what happens in this episode.
Rob is much more outwardly bothered than Sharon by their drought, waiting only minutes after she emerges from therapy to ask if she might be ready to have sex soon. The answer Sharon gives — the pills she got "may make her more receptive to sex, but less able to enjoy it" — strikes him as "a riddle," but also gets at how difficult it can be to reconcile sex with debilitating mental issues. To his credit, Rob seems understanding and accepting of Sharon's needs (or lack thereof) as she struggles to achieve normalcy through the cloud of postnatal depression. For Sharon, a good day is one where she feels "borderline nothing, but in a good way!" Add her feelings about the state of her post-baby body — she feels like "a cow in a dressing gown" — as well as the general malaise that comes with caring for an infant, and it's just as easy to understand Sharon's reluctance as it is to understand Rob's frustration.
To be fair, these are not world-shattering insights. Many couples, both fictional and real, have gone through post-baby struggles very similar to the ones on Catastrophe. But the percentage of couples with a pre-baby sex life as robust as Rob and Sharon's is … well, a lot smaller. Not even wanting sex is a new experience for Sharon, and probably a scary one. She's lost a bit of herself in motherhood, and that includes her sex drive.
While Rob deals with his physical frustration in the face of Olivia (Emmanuelle Bouaziz), a hot new French temptation at work, Sharon is looking for a different sort of outside validation. Rob's needs are purely physical, and he seems to recognize as much — not that it makes it any easier to fend off Olivia's blatant come-on. (Hey, she really liked the way he threw around that watercooler jug. I get it, Olivia.) Sharon's physical disassociation seems to run deeper, and she winds up projecting her emotional needs onto her "mum-group" friend, Sam (Susannah Fielding).
The psychology of Sharon's obsession with Sam is fascinating, and rings true even as it emits a potent cloud of cringe-comedy. Sharon has a supportive and (sort of) understanding partner in Rob, but in her current state, he's not the support system she needs. She's not only looking for someone who's been there, but who also isn't directly responsible for turning her into a black-nippled cow in a gown. ("All we do is get me pregnant," she half-laughs, half-cries to Sam. "What are we, farmers? What were we thinking?!") It's not much of a stretch to speculate that Sharon is projecting her dissatisfaction with motherhood onto Rob, and Sam represents an outside source of comfort without any sexual needs. (To be fair to Sharon, she does reach out to Fran and Milandra before she begins stalking Sam, so she at least tried to go the less-crazy route.)
The thing is, Sam's needs don't align with Sharon's. There's a low ceiling to how much Sam cares about Sharon's life — they're only mum-group friends, after all — and Sharon crashes through it right around the time she suggests a couples' getaway to Cornwall over Easter. (Seriously, Sharon! Read the room.) Basic civility and a little bit of fear led Sam to indulge Sharon longer than is right or necessary, but she's eventually forced to "break up" with her would-be bestie. "I don't have time for people in my life who … need things," she tells her. Note the similarity between this excuse and Sharon's reluctance to talk to Fergal about what's going on with their dad. If nothing else, motherhood provides a great excuse for being selfish.
An incensed Sharon handles Sam's rejection with much less grace than Rob had displayed in the face of her sex rejections, too. The two situations are different, of course, but they both serve to illustrate the pain that comes with not having your needs met. It's a smart juxtaposition on the part of Horgan and Delaney, who, as always, co-wrote this episode. They manage to keep the couple's story lines thematically linked while also acknowledging the differences between each one, gendered and otherwise. Some needs are universal — food, sleep, shelter — but a person's emotional needs are specific and fluid.
Just as Sharon is ready to explode, she gets something she didn't even realize she needed: a smile from Muireann. This sudden bonding between mother and daughter is exactly the sort of unexpected emotional beat Catastrophe does so well, and it winds up being the catalyst for Rob and Sharon to get back on the same page. And because this is Rob and Sharon, the way they get on that page is dark and weird and hilarious: Sharon gets turned on when Rob angrily imagines all the ways he'd kill Sam and her family. (He may not have any care units left for Sharon at the end of his hard day, but he's still got plenty of hate units.) Sure, their eventual coupling probably falls in the bottom tenth percentile of all the sex they've ever had, with Sharon basically functioning as a receptacle for a backed-up Rob. (Remember those pills she's taking … ) Nevertheless, they got there because Sharon is finally able to recognize his needs and put them ahead of her own. She got something she needed from Muireann, and it allows her to be available for Rob in a way she wasn't able to before.
And just like that, Sharon and Rob are a team again, albeit a team whose grounding principles are sex and contempt (mainly for the outside world, but occasionally for each other as well). That beautiful final scene, where Rob lays into Sam and her husband in the queue for the movies, showcases everything that makes these two such a strangely lovable couple. For all their performative disdain, they have a baseline love and respect for each other. The way they function may seem alien to other couples, but it works for them. Despite their history, it's never been just about the sex. Lord knows it helps, though.