there's nothing in the story that said he was cheating when he got married though?
i do think tachibana is a responsible person since he fulfilled his part of the promise with his parents when he could have simply run away and he's not the one that came on yugi but yugi was the one who asked him out and he didnt lie about his situation and everything is consensual.... and him asking to carry the business after graduating highschool shows that he is a responsible person
manipulating somebody´s feelings can be done anyway as the bastard tachibana did. The fact that yugi tolerated the forseen ending does not justifies his behavior bringing his girlfriend over yugi´s house for ex when he knew the disadvantaged position he made him agreed upon.
He complied with his parents but was a bastard overall with his girlfriend and with yugi. He didn´t care in the least.
The guy is married with children and keep cheating. What an asshole. I bet he will divorce and find a new guy. He used his wife only for statut.