I'm sorry but I didn't find a single part of this believable; the staid lady who impulsively decides on a sinful weekend, the bucket list (does anyone really do this?), the bad boy who throws over his entire life for her, the vengeful ex, the trope about small towns and small minds, the story with the emerald and the bracelet. None of it. It's probably a bit cruel, but the closest comparison I can think of is porn where they try to inject too much story and lose their way.
Christine should have gone to sin city and stayed there, I think.