i've read ahead with the japanese raws and all i'm going to say is don't waste your time with this manga, you're only going to be angry. massive spoiler ahead, click at your own risk. number 3 is very big spoiler.
1. the series is finished/axed and the ending is super dumb. only 51 chapters
2. MC ends up together with akaneya/iida but then he suddenly has ED when it's time, they still do it but he can only finish by his own hands.
3. anyways some time passes, the sex friend senpai brings iida and her friend to this storage room and has "sex" with both of them off screen. MC sees the senpai bringing iida and friend to a storage room but doesn't go and save her but rather goes to the bathroom and starts to fantasize the senpai f***ing iida and tugs one out like the cuck he is. he later then confronts iida about whether she had sex with the senpai or not, and iida says she did. so mc breaks up with her. and then time skip 6 years later and apparently iida actually never had sex with the senpai, and she actually 'loves' mc (mc is special to her that's what it literally said) but MC doesn't actually like the 'girlfriend' iida but rather a broken iida that has sex with randoms and raped. that's pretty much the end, nothing else.