When your marriage ended, you had to pay spousal support. You've done what you were told to do and paid on time every month. You even increased support when you got a raise at work.
Something that you didn't expect, though, was to find out that your ex-spouse had not mentioned that she got engaged. She didn't tell you that she had moved in with her partner or that there was wedding date set. In your mind, these things should have ended the support requirement, because she was no longer living alone.