SPOILERS! Applegate crying...

Seeing as Christy Applegates character was in on the scam, shouldn't the writer/directer have covered their asses better than showing her clearly upset, even when she was alone, with David cheating on her?
I'm referring to the part where David calls her later that night and after hanging up, she's really upset/crying.
It doesn't lend itself to the plot realistically.