Responses
Koi ni mo Naranai ?
Or
Ero Yume Aquarium (Yaoi)
Oh snap. I had read that wrong lol. That definitely looks like it could be it.
I'm sorry guys, but it's actually this one: https://www.mangago.zone/read-manga/hoshi_ni_negattari_nanka_shinai/
I was talking about the second couple. Thanks for helping me, though. (≧∀≦)
The only thing I remember is that the ML, or was it the MC? They wanted to make a planetarium, and I think it's in a school setting. It's also a black and white manga, no colors.