Gerta is an Abuser. She does not beat her husband, she does not insult him. She simply owns him.
She has carried Rick to her country from his own. He lives in her house, eats her food at her table.
Gerta has the money, so she can prevent Rick from flying home. If she doesn’t buy a ticket, he can’t go.
Gerta owns the computer. She can see every keystroke he makes. To write to a friend means every word she will read. If a friend should, thinking the discussion private, ask about Gerta, she will know it.
Rick stopped communicating by email. He would use Facebook Messenger if/when he could be alone.
Of course, Gerta didn’t allow him to be be alone very often.
Gerta owns Rick as if she bought him in a slave market.