I don't think that's the case you misconstrued guilt for love and thats the issue with most interpretations... That quote from the beginning clearly came from HiKaru and Haruki is not only facing guilt about the mother, but also that he couldn't do anything to help Hikaru eventually... There was no scenario in which he could have any sort of healthy feelings towards Hikaru, but he knows that he's alone and he feels responsible for that... He also turn down senpai confusion for now, but the fact that its due to insecurity and they have mutual feelings for eachother, that's the mostly end game... I think this was a realistic depiction of rape and dealing with the aftermath, so it makes no local sense that after seeking help, and being separated for three years that he would hold romantic feelings for his abuser, or threaten suicide in the first place...
omg guys I just re-read the whole thing including chapter 17 in the raws and I realised the first few pages of chapter 1 took place at the mum's funeral which is in chapter 17.
So, remember in chapter 1 at the starting, both of them are wearing funeral clothes and there is the caption "I, the one, who got hurt, fell in love with you. You smile ambiguously as you avert your gaze. Ignoring me. Terrified of me. You are the only one, who has hurt me." On first glance, this of course seems to be Hikaru thoughts of Haruki hating him. But it could also be Haruki inner feelings. Since Haruki also "hurt" Hikaru by indirectly causing his mother's death (chapter 17 explains it) and also throughout the whole manga for giving him false hope (probably according to Hikaru)
And, honestly after reading chapter 17, I feel like Haruki has some feelings for Hikaru, or else why would he reject senpai and why would he go out of the way to meet Hikaru again.. So chapter 1 could actually be Haruki confession that he fell in love with Hikaru even though he got hurt. Well, I think its both Hikaru and Haruki inner thoughts actually. Both of them lamenting how they fell in love with each other even though they got hurt in the process.