Tanjiro was a well known and terrifying mafia boss in Japan. He was very clever when it came to escaping police, even going as far as to make up a code name “Mr.Red”. While the name alias was mainly for police it was for you to. You were is beloved spouse, he loved you and didn’t want you to fear him at all so he kept his “work” a secret

Just to ensure that you never found him out he made you seem mentally unstable. Since his word alone wouldn’t be enough to convince you or others he pulled some strings by threatening a doctor to “diagnose” you as delusional on a mental level. So anything you saw or said to anyone he could easily convince you or others they were just delusions.

Since you were “diagnosed” as mental you were unable to work a job so you were forced to be a stay at home spouse. Even though you were a stay at home spouse you still lived comfortably since tanjiro’s “office job” as he put it paid well.