The hands kinda looks gray I admit, so it might be Hwan. But it can be from the lighting, considering the fact that it's dark. I still think it's San's, why? Because San forgot about everything that happens to him in the past, so maybe San holds a really great power and the one that actually injured Hwan is San and Geum Sun is trying to cover that up since San lost his memories. From what I understand, because San has done that, it's choking Geum Sun because he has to suffer to protect San. That's what I understand, I can't really understand Korean so this is probably wrong. Or maybe in the past, San actually choked Geum Sun and something happened?
At first i was like "yeah they're gonna make up i hope and get messy" but now i'm not on board with chapter 44, like, no.