Shane and Ilya need couples therapy. It's safe to say that being in a decade-long situationship/relationship has taken a toll on their mental health, even if they are willing to admit it or not. We get to see more of that on Ilya's part in TLG, and a few instances where Shane mentions his desperation to be with Ilya, but his carefully learned restraint and discipline keep him on the plan.
Ilya has always come to Shane's defense during his sessions with Galina and mentioned that he is afraid of messing up their time, therefore chooses not to communicate about his loneliness, depre$$ion etc., but eventually learns to admit that yes, the person that makes you the happiest can also be the reason for your pain. Shane also feels inadequate as a partner after the Boxing Day fight. If both people in the relationship are worried that the other would leave them in a difficult situation (it's all in their head, but still), it must be taking a toll on them mentally, given their headspace and the physical distance.
Although in the canon, Shane's struggles are not explored to a great extent, the recent discourse about Shane crashing out on Troy, a few other fics exploring the subtle ways in which the mtl team made him feels abnormal when they passed him off as quirky, weird or made him feel uncomfortable in his own skin have touched upon the issues that are very much part of the current world but not explored in the books. I, too, started to understand Shane's POV a little better when I learned that he is autistic. Canonically, Shane doesn't discuss this with Ilya, so both of them are holding parts of themselves and their struggles from each other. Even Shane's ED is made fun of by almost every other character in the book, maybe not with malicious intent. Still, it's not something that people try to understand.
Most importantly, both of them were taught that silence and compliance are the best solutions when facing conflict: Ilya with his family, and Shane with the hockey world.
All in all, they need a neutral party who will listen to both sides and help them communicate better. They need someone to drill it into their heads that just because you think your partner is having a more difficult time than you, addressing your pain is any less important. At the end of the day, no one understands them better than each other.
