1. I read in the tabloids that those celebrities’ relationship is on the rocks. I wonder if it can be saved?
2. Mr. Smith was afraid that after the stormy meeting, his relationship with his client was on the rocks. He decided to call his client later in the day and try to straighten things out.

The expression is often used to describe a long-term relationship or a marriage (opt.1), but it can also describe a non-romantic relationship (opt.2). The expression originates with the image of a ship that has been cast against the rocks and is about to break up. When the expression means “with ice” (as in opt.3), the ice cubes in the glass are being compared to rocks. 65