when poverty comes in at the door, love flies out of the window

When poverty comes in at the door, love flies out of the window.
When the wolf comes in at the door, love creeps out of the window.

(If a couple gets married because they are in love, but they do not have enough money, they will stop loving each other when the money runs out.) {Досл.: когда бедность входит в дверь, любовь вылетает в окно}
Худ Роман, когда пуст карман; хорош Мартын, когда есть алтын
С деньгами мил, без денег постыл

Example 1: You young folks may think you can live on love alone, but when poverty comes in at the door, love flies out of the window.(thefreedictionary.com)
Example 2: After Susan lost her job, she and her unemployed husband had a big argument. When the wolf comes in at the door, love creeps out of the window.(thefreedictionary.com)