That's ridiculous. Hiromi jumping from relationship to relationship doesn't resolve the issues he has within himself.
It's incredible how you're willing to write up a novel, yet again and again show unwillingness to read. In my very first comment in this thread, this very point has already been addressed: "The only realistic scenario after trauma is calming down over time and introducing some kind of coping mechanism".
You got burned and got issues? Tough stuff, mate, they are
never going away, no matter the time you spend in masturbatory idleness. The best you can hope for is learning to hide them more or less well, and cope with the damage internally more or less well. And guess the only way you learn to do it? By trying and doing.
It's the same for all trauma, btw: one you got from your upbrining, one you got from getting burned in a fire, whatever. You just learn to live with it in time, and that's it.
On top of that, she spent the night at Hodoka’s house without even checking in, which only made Hiromi more uncomfortable about their so-called "friendship." That’s trust issues, plain and simple.
That in particular was a perfectly normal reaction that pretty much anyone would've shown in his place.
And no, the problem in their relationship wasn't Hiromi's trauma but the total communication breakdown: from Lili expecting Hiromi to guess her unvoiced needs in chapter 33 to them both failing to talk through her relationship with Hodoka in the further five chapters and set some boundaries.
So your solution is for him to just jump into another relationship instead of fixing what’s going on inside? That’s fucking stupid. Seriously, that's terrible advice. I guarantee you, 90% of people who do that are unhappy. They never find love — they just find someone willing to put up with their bullshit. Nothing more.
I guarantee you, 100% of people in long-term relationships have issues with their partners, and whether they're happy depends only on their ability to talk and compromise - that is, the ""willingness to put up with their bullshit"". If you think there exist people who are not giving each other some bullshit over potentially decades together, much less if you imagine that bullshit can be removed in advance through any amount of time spent navel-gazing, you're completely detached from reality.
Here’s the thing — you believe your opinion is correct, but that’s ridiculously stupid because it’s just wrong.
Yeah, that's how reading opinions different from yours works before you realize yours might be misinformed. Normally people have that down by the age of six or so, but I see you're struggling with basic skills like reading acquired at that age already.