The husband
It seemed kinda conspicuous that Lianna repeatedly refered to him as Dick, rather than Richard, or Rich. Was it intended as a putdown - I'm not going to call him Richard, he's a DICK! And was it a clumsy double entrende - She's leaving Dick for a woman; she doesn't want anymore Dick in her life?
And although the husband was a jerk, I did like the fact that he didn't put her down when he was talking to the kids. They could have made him a comic book villian "Your mother is a rugmuncher!", but he did make the effort to stand up for her, at least for the kids' sake.
"My girlfriend sucked 37 d*cks!"
"In a row?"