There will be no justice for Harry because that would require Harry to do something and he's proven incapable of doing so. The first time we see Laura and Harry having sex she's obviously turned on by what's happening next door. We know this because she's much more forward and is "breaking" her rules for sex (foreshadowing?). She tells him to be as rough as he wants and Harry does...nothing. He does nothing different whatsoever and when she proposes they go a second time he says he's too tired. It's Friday night fucko, sleep in tomorrow. Give your girl what she wants. She plainly said she wanted it rougher, she plainly said she wanted to "compete" with Luca and the mystery woman but Harry just ... doesn't.
Time and time again Harry shows that not only does he not take action, he doesn't even spend time thinking about negative things. Anyone else who had an inkling of doubt would actively pursue the line of inquiry. Not Harry. Talk to your girl, demand to know what's going on. Not Harry. She is telling you your "promise" is dumb and move in with her. Not Harry. She's asking you to validate her, treat her roughly and fuck her more than once. Not Harry. She is looking genuinely crushed at times, do you ask why? Do you push until you get an answer that makes sense knowing it's what's best? Not Harry.
Harry is a lump. He's a lump who would lose Laura eventually no matter what and he'd lose Aya too if that relationship started.
I wish Luca would die in a fire. He is an asshole who has everything going his way, not even counting the ridiculous 'magic' cock. But, he also works harder on his relationship with Laura than Harry does and it's not even close. Certainly the countless orgasms affect her thinking but it's possible Luca takes her away even without them simply by paying attention and understanding her.