Chapter 41 is relatively brief, but we get a lot of personal reflection from Strike. After his revelation at the River Cafe, and with the knowledge of Charlotte's imminent wedding looming over him, he goes a bit stir-crazy, busying himself with pointless tasks. After a fruitless visit to Kath Kent's flat and call to Jerry Waldegrave, he holes up in the Tottenham, with Charlotte never far from his mind. He imagines her prepping for the wedding, waiting and hoping for him to stop it, but sticks to his resolution to let her "continue towards the prison of her own choosing: he would not call, he would not text." Instead, he does everything he can think of that might help free Leonora from the prison she did not choose.
In the midst of this brooding, he has one of his flashes of insight where he seems to understand Robin's dilemma with Matthew better than she does herself, and better than he understands his own obsession with Charlotte.
You and Matthew...Strike could see it even if she could not: the condition of being with Matthew was not to be herself.
Robin is in the midst of a reverse-alchemical process that begins with her giddiness over her engagement at the start of CC and ends in the disastrous and mock-alchemical wedding at the end of CoE. Ironically, as we learn in the start of the next chapter, Robin is, at this moment, having the conversation with Matthew that she thinks is going to fix everything; she's telling him about her longtime ambition to be an investigator. He agrees to support her. Unfortunately, like his agreeing in CC that it was her choice whether to stay with Strike, and his helping her rehearse her case for returning to work in CoE, it means nothing; as soon as they are married he'll be right back to complaining about her job and her salary. Because he's a Flobberworm. But I digress.
Strike's emotional intelligence about Robin's love life does not stop Strike from making mistakes about his own. Once he learns that Charlotte has become Mrs. Jago Ross, he makes his first convenient use of a woman as a "restaurant and brothel"--or at least a brothel--as he makes plans to go sleep with Nina again, rather than spend the night alone. He'll ghost her shortly thereafter.