Responses
If the story would be longer, I think the possibility of atonement is going to appeared at some point, bcs yes it's true that 10 years self loathing and depressed is not an easy thing to get rid of. Maybe at some point he would reminded of his dirty past self again, and then suspicious of his own feeling. But I can see Maki would be there again for him aaaaaa （/TДT)/
Why do I have this feeling that Katsumi is still depressed and the relationship he has with Maki was a way to atone his guilt for rejecting him?.. he does reciprocate Maki's feelings for him since their high school days right?... maybe I'm just too overthinking about the ending.. Katsumi probably gone through some rehabilitation while he's with Maki. 10 years of continuous self-loathing isn't so easy to overcome.