We initially meet Gosling's Dean and Williams' Cindy six years into their marriage. They have a daughter they both adore, but elsewhere their relationship has forked in opposing directions. Dean is a freewheeling man-child, satisfied with his work as a house painter and the time it affords him to spend at home--not to mention the frequent opportunities for early morning drinking it provides. Cindy, more mature and career-focused, works as a nurse at a private practice, and tries to juggle her hectic work schedule with her family's day-to-day domestic needs. The tension between the two of them seems more apparent to Cindy, as Dean's care-free attitude obfuscates the harsher realities of their life together.
There are few things more uncomfortable than witnessing a catastrophic fight between a couple, especially a couple you're familiar and friendly with. Blue Valentine elicits that same feeling of discomfort as it winds back and forth in time, teaching us how these two came to know and love each other so deeply, and then showing us how it all comes so terribly unfurled.
Cianfrance pulls few punches, and elects to avoid making either character "the bad guy" in the situation. Dean's capriciousness and drinking habits certainly lead to more trouble than anyone ought to have to endure, and his unwillingness to evolve beyond his current station in life, even for Cindy's sake, is rooted in a deep selfishness. Yet, his heartfelt love for both his wife and child are never in question, even if he can't seem to show it to Cindy in a way that actually makes her happy anymore. Similarly, Cindy is not some icy bitch, looking for a way out in light of something better coming along. Williams shows us a woman who has simply been worn to a frayed edge by the stresses of her life, Dean's sometimes antagonistic personality, and the realization that her husband is still the same impulsive boy she first met all those years ago.
Cianfrance deserves credit for giving these actors room to work. He tells this story in long takes, filled with dialogue that feels genuine. Some of it feels improvised, but rarely is it aimless. Every weird joke she tells him, every goofy song he sings her, every hopeful look they give each other early on is like a knife in the heart, knowing the hell that awaits them later in life.
Brilliant as it is, Blue Valentine will prove a tough watch for many. It's a relentlessly sad movie played with such realism that anyone who has ever experienced a tough relationship will be hard-pressed not to take it a bit personally. But that appears to be very much Cianfrance's point, to give a wrenching and unfiltered depiction of the end of a relationship we don't want to see end. It is a testament to his filmmaking, and the talents of his performers, that Blue Valentine is so remarkably successful in that goal.