They never said "lets date!" so basically they are just going with the flow.Its mostly one sided from tanaka throughout most of the story and even though he knows he loves him back,they aren't actually in a relationship where this would be considered cheating.
In the first chapters,he was surprised when tanaka said he was his "boyfriend" and was surprised that he thought they were dating.
bottom line is,he wasn't cheating on tanaka because he was never DATING tanaka in the first place.
Yeah I think so too, besides they didn't say anything about the timelines so maybe it's when Tanaka just moved in and the feelings are not yet reach to the certain limit for Oohara, just like Hirata said, Oohara doesn't want the relationship
Oohara more like Ooharasshole.
Can't believe he cheated on him to get mad two chapters after when the other is just walking with a girl. He didn't even felt bad ? He didn't even looks sorry ??
Just. What happened. Why. I feel like he just doesn't like him.