My thoughts (before I leave work for the evening, LOL)...
Billy & Mandy: I do think they'll stay together. They have both been tempted (and fallen), as one would expect when you have the chance to date nubile and hunky guys and gals. Mandy is a little spitfire, ain't she?
: She's always in hell (every week? LOL).
Andy & Shannon: Andy's a dork. Shannon should stick with Tom.
Valerie & Kaya: Valerie is one of those folks who has gotten into a situation in which she clearly wishes she could extract herself. Soon after she arrived, it seems she knew this temptation thingie was a mistake for her relationship. I agree with all others that Kaya doesn't seem nearly as committed to this gig as she, and so she gambled the dice to get a free vacation, but may have crapped out this time. If Kaya sticks it out with Valerie, it would be because he feels sorry for her. If Valerie sticks it out with Kaya (based upon the previews), she's desperate.