throw someone off balance
throw (one) off balance
1. To make one unsteady, such that one may fall. That dog threw me off balance when he knocked into my legs.
2. To confuse or upset one, typically by doing something unexpected. Jenny threw me off balance when she said she wanted to have a baby.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
throw someone off balance
COMMON If something that you are not expecting throws you off balance, it suddenly confuses or surprises you. His visit had thrown her off-balance. Her directness seemed designed to throw him off balance. Note: Verbs such as knock and catch are sometimes used instead of throw. Mullins knocked me off balance with his sudden change of subject.
Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012