Again, the problem with this story isn't with how it's developing, but how rushed the development is.
People need more time to sort out their feelings and decide to forgive someone for a trauma inflicted, but this guy got his whole worldview challenged beyond what he could handle to the point he decided to break his relations with everyone in the story and change both his appearance and mentality to the core, yet he's forgiving everyone who gave him that trauma so easily!
Each forgiveness needs to take more time. The manga isn't giving anyone the time they need to repent, so the girls end up looking like Akame ga Kill characters - show up, backstory, die get forgiven!
Let us see how being treated coldly by the protagonist affects them on a personal level, how they rationalize the situation and eventually come to understand that they screwed up each on their own separate way, and THEN have each girl start to work towards forgiveness.
At this point the guy decided to cut ties with all of them, but all it takes is a single apology and shaking a little bit for him to forgive them. I thought it wasn't good the first time it happened but I was willing to give it a pass because things could have played differently from the other 2, but that's 2 out of 3 that play exactly the same way.
Just give the story the time it needs to unfold, please! Stop rushing it!