Although the mid-February holiday celebrating love and lovers remains wildly popular, the confusion over its origins led the Catholic Church, in 1969, to drop St. Valentine's Day from the Roman calendar of official, worldwide Catholic feasts. (Those highly sought-after days are reserved for saints with more clear historical record. After all, the saints are real individuals for us to imitate.) Some parishes, however, still observe the feast of St. Valentine.
The roots of St. Valentine's Day lie in the ancient Roman festival of Lupercalia, which was celebrated on February 15. On Lupercalia, a young man would draw the name of a young woman in a lottery and would then keep the woman as a sexual companion for the year.
Pope Gelasius I was, understandably, less than thrilled with this custom. So he changed the lottery to have both young men and women draw the names of saints whom they would then emulate for the year (a change that no doubt disappointed a few young men).
There were several early martyrs named Valentine, so there are saints by this name, but they do not have romantic stories attached to them.