This phrase often implies an emotional toll, suggesting the difficulty wasn't trivial. He put her through it with his constant demands and criticism.
Pro Tip 2/3
Not Literal
It's usually metaphorical, meaning the 'it' isn't a physical ordeal but rather a challenging situation. The relentless legal battle really put him through it.
Pro Tip 3/3
Relationship Context
Often used when talking about relationships, indicating one person significantly strained the other. Their breakup was tough, she put him through it with all the arguing.