My beloved friends, let us continue to love each other since love comes from God. Everyone who loves is born of God and experiences a relationship with God. The person who refuses to love doesn't know the first thing about God, because God is love—so you can't know him if you don't love. This is how God showed his love for us: God sent his only Son into the world so we might live through him. This is the kind of love we are talking about—not that we once upon a time loved God, but that he loved us and sent his Son as a sacrifice to clear away our sins and the damage they've done to our relationship with God. 1 John 4:7-10Each holiday we celebrate, whether religious in origin or not, should serve as a reminder to us all that God wants us to remember Him, and that God loves us. On a day intended for celebration of love, it seems fitting to turn to God first. God gave us marriage so that we could know a fraction of His love during our mortal lives. God gave us courtship so that we could understand what it's like to desire love. God even gave us sexual attraction so we could understand physical love (though - we have to be careful not to step into lust).
I've briefly researched the history of St. Valentine, and though it's not certain whether or not it was in fact one man - February 14 is now celebrated as St. Valentine's day. He represented the Godly idea of supporting being in love, the act of loving, and love as a general term. God so loved the world He gave His only Son.
Love, of all things, has significant importance in a relationship with God and Christ. When we reach our eternal home, we will live in a spirit of undeniable and incredible love. Jesus died for us, because He loved us and wanted us by His side in eternity. I think it's a good idea to say Happy Valentine's Day to anyone you'd like - God wants us to be His valentine - but not just on St. Valentine's day.