For me, Jaclyn seems like she's been hurt and taking care of herself for a long time, and has no patience for "taking care of" a partner. She deserves better than Dustin or James.
Dustin's entire scuzzy existence is a mouthless blowjob and a waste of perfectly viable organs; I could have punched him through the screen for victimizing himself because he's not supposed to have sex with someone else's wife. He and Kelsey will learn nothing from this experiment because spontaneous no-boundaries irresponsible people are extremely fun... for two weeks. It's a few months later when shit hits the fan: she gets pregnant and doesn't go out with him anymore, the power's off because no one paid the bill, creditors are calling about massive credit card debt.
Tony and Heather are everything and I want them to buy a farm+raise bunnies+share a bed+jacuzzi+cook dinner for each other for all of eternity and make humongous and beautiful sweet babies. The only person who can appreciate someone who gives that much is someone who knows how much effort goes into that giving; Liliya/Aaron don't understand the value, and I don't think two weeks will be enough time to learn.