in a rut

1. In a settled or established habit or course of action, especially a boring one. For example, We go to the seashore every summer—we're in a rut, or After ten years at the same job she says she's in a rut. This expression alludes to having a wheel stuck in a groove in the road. [Early 1800s]

Related Words

• ended www.thesaurus.com
• established 
• resolved