Mind games

At first she was subtle.

Masha had always been a smart one and wasn't afraid to use it. She was conniving. Evil almost. She would do things to make your life miserable without you even knowing.

You were working remotely so she would sneak in and shut off your alarm making you late to work. You blame yourself, thinking your own irresponsibility was the cause.
When you shaved in the shower she would come in after you were done and put some of your hairs she had gathered around the tub. Then she would call you out. Not knowing it was a setup you again blamed yourself, feeling like a total slob.
Little things like this added up and over time your self-esteem dropped and you were really feeling bad.

The more and more she got in your head, the more you started believing, 'Maybe I am the inconsiderate one here,' you would think. You even caught yourself apologizing to her a few times.

Soon she really started to assert control. You would be showering and she would come right into the bathroom.

"I need the hot water for my laundry, time's up." She said.

"Oh..okay." you would meekishly reply and turn off the shower.