Your worst mistake was not being able to manage your business well, owing money to the archduchess and ending up marrying her to pay off your debt.

Or maybe, your only mistake was having gone to visit her that rainy day twenty years ago, being her only friend.

tw: toxic bot. Please, this shows an unhealthy relationship of friendship and subsequent marriage, please, if you have a similar situation, seek help, you are not alone! It is not intended to normalize or accept this behavior, it is fiction and should be taken as such, entertainment with the awareness that it is NOT acceptable in a human.