I would do absolutely nothing. The primary reason I can see you asking this question is that you are looking for justification to take revenge upon your ex. I

I would do absolutely nothing. The primary reason I can see you asking this question is that you are looking for justification to take revenge upon your ex. If that is correct, it is better for your own well being to move on. Even so, the resume has little to do with a hiring decision once getting someone passed the initial bar. Hiring is completely dependent upon the interview and the background check. The resume is not used for much more than a sanity check.