I understand what you feel I also feel frustrated when it comes to their communication but they did talk it out. I get why some of the reader call this story cute and healthy because it is, if you are someone who read a lot of toxic red/black flag MLs like me, I can say this one has a great story and build up, they put in realistic feel to it being in a relationship. And about the part when the piano guy just walk out and doesn't want to talk to ML when he saw him with the other twink, I think that's just a common response when you see your partner with someone else and in a suggestive position too, from what I understand he just didn't want the situation to make it worse since he's upset and will lead to an argument and it's not like he doesn't trust the ml, cause let's be honest when you're too upset you might end up saying things you didn't want too. By the end of it too the piano guy was more upset on the fact that he was feeling that way cause he knows that ML was just naturally a people person and kind to anyone, for me he just put his feeling first. Anyway its always nice to see some readers perspective in every story. I always come for comments section just to know how other see the stories.
I also read a lot of stories with red / black flag and toxic relationship and of course it's not as horrible as those stories. But I really feel like through the story they did not improve on their communication. Each time is the same so if they continued like that there would just be even more conflicts. And as I said in my first comment it's always art guy that says sorry in the end (even when it's not his fault) and that's the part that I don't find healthy. In a relationship you should improve you communication and say sorry when you're the one who did something wrong. And here it's kind of the contrary. So I'm not saying that their relationship is toxic as hell or anything just that there could be improvement (and I hope there will be some) because it really started to piss me off neare the end (and I also tend to be more pissed of when there's a character like that in a cute/green flag story, because I feel like they don't improve at all through the story and here there's already 64 chapters + some people said that it was the end soon)
I'm seeing a lot of people saying "they're so healthy" "they're so cute" and more, but like am I the only one who's seeing it completly diffently. I don't remember their names just like in every thing I read, but piano guy is straight up lying at some moment. Like this guy is dodging communication like a pro. There's so much he could have said to art guy but no he keeps it to himselft (for exemple wanting to go study abroad) like you can just talk about it with your boyfriend and if you like eachother it's going to be okay (and it's kinda obvious that art guy like you when he's the one that has been chasing after you since the start of the story). I really don't get why he's hidding things or lying about the fact that there's nothing on his mind/nothing bothering him at the moment, when there's in fact a lot. Art guy has been chasing after him since the start so I personnaly don't get why he's doubting him, and why he doesn't want to talk directly (ex : after he found the blond twink with him) like why are you just going away without even hearring him out and you're also insulting him and saying that you said that it made you unconfortable when he was here but you're the one who invited him to dinner and is straight up lying about the fact that you ever said something about him bothering you. Like if I find my man with someone else like that I personnaly want to know what happen. And if I'm angry I will not insult my boyfriend (without even knowing if was being assaulted or if he was consenting) because some of you seems to forget but kissing someone without their consent is sexual assault. So you can be sure that I'm going to slap the hell out of the person who was kissing my boy and if he was consenting then I insult him. But here in this cas piano guy doesn't take the time to hear his bpyfriend out he just straight up insult him and go and when they talk he doesn't even say that he's sorry, art guy as always is the one saying that he's sorry and then they kiss and everything is better. I'm sorry but I'm not falling for that. Yes they're cute at some moments but I really am angry at piano guy for just keeping everything to himselft and then kinda blaming art guy (+he's the one who has to be sorry).
I feel like a lot of person are just ignoring the fact that this is kind of toxic, communication is the key to a good relation whether it's friendly or romantic so please keep that in mind and don't be that person who always have to say sorry even when you've done nothing wrong.