Unfortunately for The Drama, I think they do talk about it
This is my take of the day: I think married, post-TLG Shane and Ilya are decent at healthy communication. In order to do what they have done, namely, become two openly queer professional athletes who end up married on the same team, they've had to become intensely vulnerable with each other.
I know they're hockey players steeped in a rigid culture. I know they both have a cocktail of issues (hyper masculinity, internalized homophobia, childhood abandonment issues, etc.). They are definitely a part of the culture in which they were raised, but I want to talk about the ways they are different from those around them. And those differences mean they have the pathways in which to speak through their issues.
I'm not saying they have perfect, therapy-speak conversations. It's something to the side of that. They don't have the perfect words, but they know how to move through each other's moods and quirks because of the nature of how they finally got together, not in spite of it.
I know that falling in love or being in a relationship doesn't fix your issues, and there's another argument to be made about the trauma that could stem from their years of hiding, but I think the way that Shane and Ilya come together in the first hurdle (HR: coming to the cottage, admitting feelings, planning for the future) and the second (TLG: navigating long distance, Ilya's depression, Shane's shame) required them both to expose themselves in a way that wouldn't be possible if they were both just heterosexual hockey bros who either married their first girlfriend or were simply notorious womanizers.
And that's because of their circumstances, not in spite of them. I'm not saying being queer makes you automatically enlightened, but it does make you think more than a person fully steeped in dominant culture. It's the classic thing, when you're straight you don't have to come out, people assume that's what you are and therefore you don't have to think about it. When your desires, thoughts, or identity don't match the mainstream, it means you will think about them, rationalize them, analyze them, make plans to conceal them, make plans to act on them, and more. This can stunt you, for sure. It can make you mean and closed off and bitter, but that doesn't happen for Shane and Ilya because they have each other.
This is why Scott Hunter is an important part of the story. He's different from them because he has never rooted himself in his sexuality. He gets a fix where he can and puts it aside on other days. There's no long term string connecting him to being gay until he meets Kip, and I like that he's in his thirties in the show, it really makes it more weighted just how long he's gone without any sort of validation of this part of his desires. The way he moves too quickly, too intensely, their relationship burning hot and fast with immediate confessions of feelings, an instant intimate relationship, and living together, indicates his level of inexperience but desperation to finally have this. Scott didn't have an Ilya Rozanov to look at him at 19 in the showers and say "it's okay to desire something."
But Shane and Ilya, unknowingly, go on this journey of self-discovery together. They have different stories: Shane isn't gay, he's just doing this one thing with Ilya before he finds a girl and gets married. Again. And Again. And Again. Ilya isn't ashamed of his queerness, but operates in the concrete view that he could never actually have something long-term in that realm. Importantly to me, they have both gone through something. A transformation. They both had to come to terms with who they are and what they are to each other. Cisgender, White, Heterosexual men definitely have issues, but their issues in general aren't about their identity not matching the mainstream and finding how to fit within it.
So when it comes to disagreements, tiffs, little tilts to their tone of voice that indicate the other person is pissed-off, annoyed, or downright angry, I think that the other one would say "Wait, what's wrong? Can we talk about it?" because they've gone through so much! They've had to think and plan and rationalize and weigh the odds and do so much critical thinking about their relationship, so by the time they're married, on the same team, moving in the same direction, I just think that they would be able to talk. I think they have the tools. I think they're great at the little talks, the "you seemed weird earlier is something going on?" type talks. They know how to listen and comfort each other with their presence (it literally starts at the cottage!) and they also both take comfort in the physicality of their relationship, and I think over time their communication becomes more integrated with sex, so they're not avoiding communication by having sex, like they were in TLG. They are making their own language. They are analyzing, interpreting, and creating, all higher order thinking skills.
It's not that they never fight. It's that their fights are genuinely formed from the stresses of queer, public-facing, work pressure-based, married life, and not always from their own internal issues or inherent "flaws" from the time before. Shane doesn't have the same issues he had when they were hooking up, and neither does Ilya. It's not that they never hide their feelings, but hiding their feelings stems from not wanting to stress the other person out or other factors, not from an inability to be vulnerable. They had to expose everything to the other person in order to make this situation work. They admitted feelings and then immediately started a 4-year long term relationship that culminates in a marriage. Not a break-up, not a toxic relationship-- an honest to god relationship that uplifts them both. They've dealt with a lot, they can handle a little healthy communication. They can fight about big things and then slunk back to each other and be like "well that was bad, let's re-do?" If we are operating under a belief that people can learn lessons and grow, Shane and Ilya will only become better at being together as time goes on.
I still like making them a little less mature in fic though. As a treat.