Williams didn’t have a chance, really, but in another year, amid a different set of nominees, things might be different.

The same shift in luck applies to the couple that comprises this film’s core: one year, blissful; another, miserable. Cindy (Williams) is a nurse, while her husband, Dean (Ryan Gosling, “Lars and the Real Girl”), is a housepainter who makes up in drinking what he lacks in ambition. Together, they have a darling daughter (newcomer Faith Wladyka), but even she can’t bond them tight enough to keep their divide from fatally widening.

“Valentine” starts in the now, then gradually introduces scenes from their courtship that not only show them in happier days, but demonstrate that they likely were doomed from the start. When a relationship begins with deeply rooted feelings of uncertainty and jealousy, no piece of paper will alter that dynamic.

It’s a shame that director/co-writer Derek Cianfrance’s film attracted more attention for its frank sex scenes between its married characters (its initial NC-17 rating was appealed to an R) than its overall dramatic worth, which is hefty. While Gosling occasionally overplays Dean as a Nic Cage cartoon, Williams’ performance is dead-on perfect, remarkably brave and free of vanity.

“Blue Valentine” benefits from an emotionally lo-fi score by indie-folk rockers Grizzly Bear that matches Cianfrance’s visuals. When the end credits explode in fireworks, so do the hairs on your arms. Now that you’re in control at home, turn it up loud. —Rod Lott