well....nobody likes cheating but we know the situation better now with the update so.... ╮(￣▽￣")╭
eheheh.....I'm not good at explaining this....
Cheating is not the same as slutting. Whether he has an open relationship with his sensei or not, our poor seme has been used and forced into an unpleasant, undesired situation. That's what the problem is. The relationship is no longer about just the uke and his ex.
Maybe its not so undesirable for the seme, now that it seems he really cares for him? Not every uke will be a virgin or emotionally intact or not have history, I think he adds color to the seme's previously dull life and if he's making a conscious decision that he wants him in his life then he must enjoy being with him more than feeling the unpleasantness.
people here slut shaming, bashing him for being a 'cheater', I'm just like maybe they just got back together? maybe its an open relationship? maybe he's TESTING the guy? maybe I'm wrong about all this but still it's up to his lover to decide what goes cuz its not like he's dating any of us!