That's the thing I don't get but which pops up a lot in manga. A loved one (bf or gf) blocking the way of the hero(ine) solely because THEY don't think it's right for them.
I get the point that Riku's had a hard life and bloodshed is all he knows but damnit woman if you want to help him you support him, you BE the calm in his life he needs, the UNCONDITIONAL LOVE he's never had in his life. Instead you give him conditions...you force him to choose between his life's passion and your crush? It's asinine.
Boxing is a harsh sport but so is MMA, WWE, football, hockey, soccer, baseball, etc. It's years of long hard work for only the chance of victory with no guarantee and things can go wrong and you get hurt, suffer career ending or life debilitating injuries, or even god forbid killed during it. That doesn't mean you should stop someone from it unless they have serious medical issues that could threaten their life. You SUPPORT them. Because that is what THEY need in their life. Not your judgments.
if you love s.one then you love everything about him.
she just loves her self and she just want her happiness and she didnt really care about his happiness, otherwise she wont try to make him quit his passion.