The manga is about a guy who had and older guy friend/tutor who taught him about "adult" things. When the kid gets into high school his older friend moves away into his own apartment where he meets a couple of other people and things get complicated. Instead of a love triangle its a love square?. His friend turns out to be a possessive, manipulative guy with glasses.

There's more but that's the best I can summarize it.

Appreciate the help.

Is it Love x Ero?