While I have never been to Mexico myself, I can't imagine it would be a healthy place for an active addict to spend time.
Your picture is very lovely, and I can only just imagine the pain you are feeling over the cancellation of your wedding. Perhaps it might not be the best idea to torture yourself by continuing to look at these sorts of photos. For the sake of your own health and sanity, it might be a good idea to pack those photos away in a box somewhere and then, perhaps, throw them out when you feel stronger.
It is a shame that you will lose the money spent on those tickets. But it might be healthier for you in the long run to not go with him since it will merely send him mixed signals about your intentions.
Huge hugs and prayers to you as you work your way through all of this.
HG