I like this ship but I think uke shouldn't cheat. He should broke up at first.

But the other tiger cheated on him too

Actually, we don't know about that. We just hear, that he has a fiance (this is not okey, he is a liar) but we don't know if he sleep with her or is this just arrangement or something.
Uke shouldn't done this, because I think even if someone cheat on you, you should be better and don't do it in revenge. He should just broke up.