Nooo you’re completely fine, don’t worry. And this is the spicy stuff I like to see YESSS

Hashirama will be deeply hurt, but the feelings of bitterness won’t register for a while. It’s only if he gets to thinking about it that he’d be angry at her, and at the other man. His primary concern is that he’s done something wrong. Has he been neglecting her? Treating her wrong? To the point that she’d seek the comfort of another man? Once he’d confirmed that not to be the case, because Hashirama just isn’t the type to neglect his s/o, that’s when the frustration would cloud his mind. But he’s also the type to confront her early on rather than wait it out, and in a very civil, non-confrontational way, because he wants to solve it before it starts eating at him too much. Finding out it was her brother would be a relief, but also incredibly funny. He’d be the one who would treat it as a long standing joke afterward. He’d probably also apologize for jumping to conclusions

Tobirama backs away from the situation all together to try and consider it ‘logically’. Truthfully, he’ll be too blinded by anger to really come to any rational conclusions, so his isolation will only make it worse. Then, once he can’t practice restraint any longer, he confronts her and lets her have it. Originally, he’d probably planned to start a civil discussion to figure out what was going on, but his anger wouldn’t allow that. He’s just too combative. So he’d probably be yelling and accusing her, giving her almost no opportunities to explain herself. It’s only after he’d vented out his frustration that he’d offer enough pause for her to actually explain the situation. He might not believe it at first, even if it did relieve him. Only after continuing the discussion—more like argument on Tobirama’s part, would he give in and see the mistake he’d made. I honestly don’t think he’d apologize, not unless he had somehow scared her and hurt her feelings to the point where she cried or something. In that case, he’d probably overlook his pride in favor of consoling her and telling her that it was his mistake

Once Madara suspects that something is going on he starts plotting. Investigates the situation a little more, but with a preconcieved notion that she’s definitely cheating and it’s unlikely that he’s just not understanding the situation or that he’s missed something. That in mind, he’d confront her randomly to catch her off guard and kind of intimidate her? Will be the “don’t act like you don’t know what I’m talking about” guy, not directly addressing the subject, but approaching it in more of a way where he hopes that she confesses. Once all the miscommunication and beating around the bush is out of the way, and he finds out it was just her brother, he’d definitely feel naive and impulsive and just all around pretty dumb. Would probably have to step back and calm down for a while before he came back, and would act like it never happened, which he knows is unfair, but it would hurt his pride to talk about it or even think about it. It would just start a bad argument tbh