So, the artist dropped the manga lol. I have to say, I didn’t like this. It was quite confusing, boring, and basically a bunch of glorified sexual assault. My top choice was the childhood best friend, because I felt that he was the only trope that was done well, and even somewhat likable. I just suggest you don’t read this. Save the trouble for a well written polyamory relationship or harem. I suggest the manga “I Wanna Die Before I'm 30“, it’s a great polyamory relationship, and a very entertaining story.
Bokura To Usagi No Koi Wa Sensou