I'll never be able to confirm to whom the alleged St. Valentine sent his love letter, as his identity is surrounded more by myth than fact.
Research yielded, in addition, that he was removed from the Church calendar because his origin was deemed to be purely legendary. See what Wikipedia has to say. I also consulted the Catholic Encyclopedia. And then there's Fact Monster.
Well, we can't stop love from being celebrated anyway. Just thought we should be more aware of why.
Don't get me started on Halloween.