But love hardly needs the aid of religion. Everyone in the post-Christian West knows what love is.
"Love is all you need," the Beatles intoned.
"Love is love" and "Love wins" were the emotionally satisfying rallying cries of the movement for same-sex marriage.
We apparently do not need religion to tell us that love reigns supreme as the highest good in our culture.
Even religiously inflected notions of love fail to distinguish themselves from modern, romantic ones. Plenty of brides and grooms choose secular songs and readings for their church weddings.
The allure of romantic and erotic love is so strong many faith leaders struggle to convince the faithful that religious marriage is any different from marriage in a civil or cultural sense.
Religion does have something important to say to us when our conceptions of love are incomplete, mistaken or break down.
Evangelicals take flak for promoting premarital sexual abstinence with the mantra "True love waits." It's easy to laugh when Catholics tell their youths that condoms may protect against sexually transmitted diseases, but they cannot prevent a broken heart.
But the three most powerful words in the English language are not "I love you," but rather "I forgive you."
Precisely because so many of us fall short of the ideal, religion offers the promise of forgiveness and reconciliation, not just when we neglect to give our lovers the very best of ourselves, but when we fail in any area of life.
And it is at the level of forgiveness that our faith traditions add something distinctive — and distinctively religious — to our broken hearts and broken relationships.
We find love on our own, without God: at school, at work, on dating apps. More and more men and women pursue romance and eroticism quite apart from the guidance of religion, with its cautions, limits and prohibitions.
But whether religious or not, every lover will, from time to time, stand in need of forgiveness for transgressions great or small. And here, our faith traditions shine because they model and promote authentic healing and restoration, even and especially when a passionate, magical Valentine's Day feels far off.
Forgiveness is also a vital part of relationships between nations, for the rule of justice and law among them depends ultimately on forgiveness and reconciliation in human hearts.
The old song says love is "the only thing that there's just too little of." But that's demonstrably untrue. We could use more love, of course. But what we really need is a renewed sense of what love is. And love is far from the only thing we need. It cannot be sustained without less fashionable virtues such as constancy, fidelity and, yes, forgiveness.
Few lovers will have a night of passion as depicted in "Fifty Shades Darker." I suspect few really want to. Far from the realm of fantasy, real relationships between men and women are often strained by disappointment and unmet expectations. Before we truly experience love this Valentine's Day or any day, we may need to give or receive forgiveness.
— Jacob Lupfer is a contributing editor at Religion News Service and a doctoral candidate in political science at Georgetown University.