So the village is built and everyone is alive and madara and hashirama are the respective clan heads. Madara gets it in his head that he wants to court tobirama and he doesn't consult anyone because hashirama would cry on him and izuna would probably curse him, he just goes for it, tells tobirama to allow him to be courted by madara. Tobirama, who is neither here nor there about romance stuff is just like ok why not let me see what you've got.

I assume here that clan head Madara, and personal life Madara are different people, where clan head madara is decisive and doesnt take shit from anyone. While personal Madara would be someone who asks for opinions before doing something, like asking Izuna how he feels about this or that, checking in with his partner before deciding something. So that's what he does while courting tobirama, asks him about everything before he makes a decision. Everyday, where do you wanna have lunch? What would you like for dinner? Would you like me to help you with that? Would you like me to get that for you?

It all sounds very caring and Madara is, he's attentive and watches for what Tobirama likes or dislikes and all, but in the end he's always checking in with Tobirama. For Tobirama, this is what he doesn't like. He doesn't want his partner asking him to make the decisions, he wants for the decisions to be made for him while fully knowing what Tobirama himself would choose. He makes decisions day in day out at work and in their clan helping Hashirama lead, maybe he just wants his personal life for someone to know him and make decisions for him.

So here comes in Tajima, he retired when he was injured on the field, leaving him with some kind of permanent injury (somewhere idk). He's experienced with romance, raising kids, leading his clan, and now is enjoying retired life giving Madara advice as and when he needs. He sees Madara and Tobirama courting, and he can tell that both of them are not content, something is missing for the both of them.

Tajima swoops in and is like, son let me show you how it's done. Madara and Tobirama put their courting on hold (stay with me idk if thats possible but for shits and giggles imma say yes) and Tajima tells Tobirama that Tajima will be courting him now. He knows Tobirama would protest if he didnt like it, so he doesnt bother asking, just informs him. Tobirama is like what the hell why not let's try it. Never know until you try right.

Tajima has a ruthless personality, he doesn't stop until he gets what he wants. He has more experience with people and know not everyone can be treated the same, and how he personally liked to be romanced may not be how Tobirama would like to be romanced. So from what he observed, he finds out Tobirama doesn't like stupid questions, in work and in life. He may tolerate it for children but from adults he'd glare at you so hard you felt your blood chilling. So no stupid questions, any obvious observations and even the little things he noticed about Tobirama, Tajima doesn't ask, he just does.

If he has time or wants to he cooks and drops off lunch for Tobirama, or if not then he walks in when Tobirama is free (he illegally procured his schedule) and tells him Tajima is bringing him to lunch. He doesn't ask what he wants to eat, he just brings him there while chatting. When he buys things for Tobirama he just does, whether he likes them or not he doesn't ask, just observes when he gives them and makes a note for next time depending on Tobirama's face. He makes plans, dates, making sure tobirama is free and telling him when and where and what to wear.

Tobirama surprisingly just goes with it. He never thought he'd be so okay with someone doing things for him and to him without his input. He's always been meticulous in his own work, he'd keel over from exhaustion before he delegated any of his work to anyone because they just wouldn't do as good a job as him. So this, Tajima making decisions for him, doing things for him, without even asking him, and he liked it. He liked not having to think about it, not having to arrange and plan their dates, or what he should eat for lunch when he normally barely eats at all.

With Madara, Tobirama assumed with how he was the Uchiha clan head and an elder brother he would have more of a pushy personality. But Madara gave too much and rarely took.

Tobirama just needed to be able to shut off his brain with his partner and let them take the lead. He knew exactly what he wanted to do in his career and experiments, but he didn't care in his personal life so long as the people he loved were still in it.

Tajima, somehow, it went from showing his son how it's done to thinking hm tobirama is very alike himself in work, meticulous and specific, suffers no fools. But in his personal life he seemed to match Tajima perfectly. Tajima liked control, to anticipate his partner and provide. And tobirama liked to be anticipated for and provided for. It was a perfect fit.

Madara: dad i get it you can stop courting tobirama now

Tajima: hmmm i think I'll keep him

Madara: dad wtf