Yeah, I totally agree with everything you said. Yaoi tends to down size how big problems actually are and apparently a psychologists don't exist is this world, all psychological problems are fixed with love and sex. Absurd. In this kind of scenario, Haruto is the best option. In real life he's part of the problem.
I completely agree, the whole bed scene made me totally uncomfortable with the story. I started feeling suspicious the minute Haruto went "I don't have a futon for guests" - I immediately thought "Oh surely not, don't just be yaoi about it PLEASE" but lo and behold...
I think it is clear throughout the story that Haruto is complete shit at dealing with Ren's situation, but because it's from Haruto's perspective it feels oddly off-kilter somehow. And you're right, his internal monologue is actually sorta disturbing. I think it's all probably deliberate, so in that sense it's well done. But I'm not surprised at all that Ren left. That poor kid.
I'm going to go re-read Cut now. Two damaged kids together feels far healthier than a damaged kid with an adult who is clueless to the point of making things worse.
First he hits the kid then he sleeps with a child who clearly has trauma and was sexually abused for years. How are you swayed to have sex after a child vents to you his miserable life of pain like what sensible adult even does such a thing. I literally have no words for uttterly stupid Haruto is. He’s a grown man who should know better and continues to sink into his desires the fact that he even mentally mentioned that Ren should be used to it even unconsciously really is telling of Haruto knowing fuck all to help this kid. Ren needs therapy not an adult who’s half assed in trying to help Ren and also be his lover, Haruto is making the situation incredibly worse despite any of his efforts. What is with these plots of a victim turning for help and instead of properly seeking help for them, the savior puts a bandaid on the situation and resorts to sex as some ridiculous cure all, I’ve noticef that this also another trope within yaoi-the someone died I helped mentally just by cooking for them and having sex instead of seeking proper therapy approach seen especially with I’m dating my dead sibling’s lover now plot.