United States of Tara is a TV show by Showtime, so at least it has a realistic amount of sex and swearing. It's a drama, and a pretty depressing one at that, so not the kind of thing you'd want to rewatch all the time, but it's nevertheless worth checking out.
Many people have some kind of quirk or issue that affects their lives, their relationships with those around them, and even how they're seen by strangers. Naturally, whenever Hollywood touches upon representing such an often marginalised group they'll feel compelled to watch the result, no matter how unrealistically they're being depicted.
By Hollywood's standards, I gather United States of Tara is an amazingly realistic depiction of multiples, people afflicted by what psychiatrists call dissociative identity disorder, and the public call multiple personalities. Robert Pirsig said it best, however, that you don't have a personality, you are a personality, so such slang terms really kind of miss the point about just what constitutes a person in the first place.
Rather than anything so trite in films and rare in real life as a mere two people sharing a body, finally revealed in a Psycho-style plot twist, this show instead focuses on the realistic implications of cohabiting your body with several others, such as time loss, constantly apologising for what your body's cohabiters have done when you weren't around, and putting up with well meaning but often clueless psychiatrists. It shows the protagonist's whole family struggling to stay together amidst the chaos, and it shows her delving into her traumatic past in search of answers.
All in all, this is the most realistic depiction such people are likely to get out of Hollywood for a while, so on that basis alone I'd recommend this show. It's also very good in its own right. Check it out.