O que significa a expressão to put through the wringer?

Not very proud to say this, but I'm on the third or fourth episode of Love is blind, a reality show about men and women seeking romance and marriage. And during one of the proposals a newly-engaged woman said something about her fiance that caught my ear: "He really put me through the wringer". What does she mean by that?

The thing is, before I tell you about the expression, I need to clarify the context of the show. It's just a bunch of singles trying to match and get engaged to each other without ever seeing each other face-to-face. They're separated by a thin wall and are only allowed to meet when they finally make a final match. One of the men were having a hard time deciding which woman to pick, and ended up putting three women through the wringer. So by now you have probably realized the meaning of the expression is not positive. 

If you put someone through the wringer, you subject them to some ordeal, trial, or punishment, or you make them undergo an unpleasant experience.