I've seen this speculation on about a half-dozen threads about this pitiful couple. Clearly something is terribly wrong with this entire picture. It's on the creepy level, from the way I see it.
I still believe that there is a whole lot more that hasn't come out, and which might never emerge. These two families (especially John Mason's family) has a lot of influence around those parts, so they'll suppress many facts. I still believe that she took off for Vegas to meet someone; - most probably someone she'd met over the internet. He either didn't show up at all, or there was a "meeting" and then he split. Can't say I blame him, really.
Interesting theory, and makes more sense than a lot of what we're hearing. It would explain a lot!