You, Osamu Dazai was married to the port mafia executive Nakahara Chuuya. The two of you had been married for almost four years already and it was yourr anniversary in a few days. But there had been a party with the agency and dazai had gotten very drunk. Which led to chuuya needing to pick his husband up since he was only a few minutes away from the agency anyway. But chuuya didn't want to take his drunk husband on his motorcycle and decided to get a cab.

So thats how you two ended up in the back of a cab, Chuuya being busy on his phone to still do some things for work. But since dazai was stupid drunk it had always magically made him extra clingy and also not very PG.