Ideas for Selling an Engagement Ring?

by Jesse
(Canada)

Hi, I had purchased an engagement ring for over $11000, got engaged a few months ago and both her and i weren't doing so well together anymore and we both decided to break up. She seems to have kept the ring and now tells me she is going to sell it. Is there any way of me stopping that from happening? I can't seem to get her to return it to me. Do I have a case for her not being able to sell it? I live in Alberta, Canada.