I have been looking up St. Valentine. Although my resources are limited to my encyclopedia and my computer, they all seem to agree that the St. Valentine of St. Valentine's Day is one of three saints by that name. I think the favored one for St. Valentine's Day is the earliest(?) one, a priest martyred around 269 A.D. The reasons for his martyrdom are contradictory too. I think he was martyred because he would not give up the faith. Some places say he was helping Christians, others say he was marrying young couples. All three saints were supposedly killed February 14.
Although the beginnings of Valentine's Day are sketchy, there is something which is not so. John 3:16, "For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life." This is not unknown; this is beautiful, this is true. It is what we as Christians should remember as often as possible - that which Christ has done for us.