how can I prove this?

A year ago I started working at the same company as my wife and have been very well recived. As both of us are hard working , helpful to other employees, and are willing to go the extra mile for the company when needed. Recently I put in for a job posting...in fact the extact same position has been posted three times in the last 5 or 6 months. When I didn't get it the first time I wasn't surrprized as I was still a temp. When my super told it was because of lack of experiance I took on a volintary job that would give me much of that. Second posting I was told I didn't interveiw as well as the first time but they would allow me to train as a back-up. However they hired someone else that had no experiance. Trained for about two months third interveiw changes in managment ment a new super. I was told I didn't posses enough experiance. Super asked other employees for their input... they said give him the job. Somehow the super decided that ment I needed another person on another shift to evaluate me. I did that he suggested they give me the job....nothing!! I followed this up through the employee commitee( our version of a union greivece). Which resulted in two personal meetings with management. It was during the second that I realized I was getting an answer when the operations manager took it upon himself to speak for both supers and claim that a single answer given at all three interviews had caused the supers concern( because the operations manager isn't supposed to be involved with the hireing process). Only then did I realize that just before the third interveiw my wife and another co-worker had filed a complaint against another super who is a freind of said operations manager. I'm certain now that the sudden change of attitude towards me is in direct retaiation to the waves my wife made with that complaint. My question... how can I prove this? Thank You.

The facts themselves could offer proof but other evidence or testimony is likely needed if you want to pursue this.

You could subpoena records or depose witnesses if you feel they know something that would help your case.