Cheri - SPOILERS

No one has said anything here about the character Cheri. I thought she was the least reprehensible person in the film.
Carey is a brute, a rapist who delights in cruel behavior to women and who ends up taking his best friend's wife. Even with her at the end, he is only interested in whether he is going to get an orgasm or not, and refuses her request that the one thing she wants is to simply be held. He has to argue with her and immediately try to turn it into something erotic. He is possibly fighting his own homosexual urges and therefore has to psyche himself up for "performing" as seen in the first scene. As many people have said on this board, he is a horrible misogynist. And to the person who said he was interested in his "expensive" sheets, the joke is that 380 count sheets are something you get at Walmart.
Ben Stiller's character is a self-centered creep who sneaks off with his friend's wife.
The other guy is so focused on himself he can only find satisfaction in auto-eroticism.
None of these men are capable of having a mature sexual relationship of mutual respect, tenderness, and interaction.
Keener's character is a cold sarcastic person, who isn't able to feel much loving emotion toward a partner, and can't bother to interact verbally. She is into it only for pleasure, as far as we can see.
The wife isn't as selfish as the others, but if you have that much of a disconnect with your self-obsessed husband, why not try to work it out in sex therapy sessions with a counselor, instead of going off with his friend?
Cheri seemed to me to be the most adult and authentic person, willing to risk her feelings. She ends up miserable because Keener is carrying out her usual isolation mode. She seems "needy" in this film only because she is the only one who is expressing a normal desire to connect emotionally at a deep level.

Altogether, I agree with the poster who says it is a "realistic" film in that there are immature self-centered people like this everywhere, but spending time in their miserable company is something I wouldn't choose to do.