Well ure right but first: he did state why is he doing this ( cuz of his past with his father , well ik its not a valid cause and its stupid but the author wanted it this way so). Second : the guy didn't even like her so u can't compare between the two. Third: he's the mc after all and its a yaoi so don't expect him to be with her so worst or not doesn't matter the plot goes like that ...
I don't think you're understanding what I'm trying to say. even if he didn't like her that doesn't mean the cheating is ok :/ and I know he's the mc and he's not going to end up with the girl but again, that doesn't justify him cheating twice.
everybody's saying the girl got karma for being a cheating bitch but then isnt the guy even worse bc he did it twice?