I love it but idk why I'm a little upset

Same. I loved reading this but I'm left slightly upset.

For me it was because of how differently they adapted--or failed to adapt--to the outside world. Kichou stepped easily into the fortune that has been left in his charge, seemingly unmarked by his experiences in the brothel, but it's clear Kagerou is deeply scarred by the brothel and cannot stop thinking about the men he had to sleep with. He very clearly could not build a normal life on his own. He's so fragile. I love this manga dearly but the ending is very poignant.

I looked at it as being incomplete, but in a good way. They are like 20-24 they still have many years ahead of them to adapt and build as members in society. Kichou even suggested that they attend college, he’s secure in the work force because of his affluent family so there’s not a problem there, and it’s not like he’s against the idea of kagerou growing as an adult and getting a job himself. They have time.