Damn, making me think of my ex with this particular thing- way back before we dated, she was known to cut her wrists. One of the things I wanted to make sure about was to never have her sink that low again, that just my presence would be enough to keep her calm and content, at the very least. Didn't stay that way, ultimately, but still. I feel like I maybe helped her feel okay with herself for a year or so, at least.
There's a bit of my own upbringing in the 'neglect' angle of Mahiru's general backstory, too, which only more recently sunk in. To be fair, I also had three older sisters each born within a year or two of each other and myself in a chain, and we kinda took care of each other more than our parents did us. Let alone things worse than neglect that flared up for all of us. No wonder I kinda fell apart after losing my job and my ex within the same year, and only now figuring out just how broken I was and probably should have been taking care of my mental health already at the time.
I will note that's one thing manga never deals with: characters who need professional help getting it. The fantasy of having a loving companion that would help you to heal and that's all you need, when reality... often doesn't work like that.
It's a nice fantasy, though. A nice bit of escapism.
Oh, and to clarify on my ex... nothing particularly grim happened, we just separated amicably, but then I had a mental breakdown while we were merely awkward roommates, and thus I don't blame her for getting away from me in that state with us not being together anymore. I've been feeling like shit for not getting the help I needed before that happened, after I realized what actually went down. She even prodded me to get help, same as she was getting at the time, but I refused to listen.
Oh yeah, the neglect angle makes me think about HoriMiya, too. Specifically, Kyoko Hori's parents, who, though they probably did love their kids, couldn't spend nearly enough time at home to actually raise them because they were so busy, and the father in particular spent so much time away from home working that Kyoko started calling him by his given name instead of 'dad'. I know that story kinda hit home, a bit, too, as Kyoko's situation reminded me of my eldest sister, who had to basically become a replacement mom to myself and our other two sisters.