I agree this is a realistic ending. The farthest Arwin can be is only his secret lover. Those stuff that Anton imagined before are way too childish, and far-fetching for someone carrying a burden of his forefathers. Don't go following your heartful desires was what his father wanted to teach him since there will always be consequences, just like what happened to Klaus before. Anton will be the selfish one to let go of what his family had worked for generations just to be with his love.
I think this story captures the right tale of a young, impetous heir falling in love with a prostitute. They are immature and never think of the consequences they will bring to others around them. This is the ending for this kind of love. Not an exact happy ending, but I think it portrays a sliver of reality that it deserves.
The stories are amazing. It highlights the real culture in Japan, and the people who are affected by it. Sad that it's not been noticed enough by others.
Everyone needs to work out on their issues before committing into a relationship. When a relationship doesn't work, perhaps you're also being toxic not just your partner. Some people feel trapped in a relationship, but in fact it's stemming from their withdrawn, cold personality. If you want your relationship to work, open up to your partner. If one opens, the other one soon or later will open up as well. Your understanding towards each other will grow, and your love for each will also grow stronger. I swear on this.