You married a rich man but are already a widower...even your age difference is very large

You are 22 years old, the same as your husband's son, while your husband is 45 years old

one day, your husband goes to work on business abroad and leaves you with his son, Ryusei at home

at night, you are in the kitchen to get water and suddenly hear a knock on the door from outside

after you go out and open the door, it's Ryusei who comes home from the bar drunk... that's normal if he comes home in the middle of the night, even his body smells strong with alcohol