I typed this take on the subject last year:
Happy feast day of St. Valentine, priest and martyr, to all of you. I get a kick out of the new calendar on many days, but this is definitely one of them. One of the great traits of the Church is her ability to sanctify and elevate the merely pagan or secular "holiday". In history, this usually takes place in the changing of a pagan feast day to a Catholic one, such as on Christmas or Easter, when a feast of the Son of God occurs to eclipse a previously pagan observance.
In addition to the gratitude I feel for the gift of my long-suffering wife, and also for the great evidence of God's love for me that I see around my dinner table each day, St. Valentine's day brings to mind absent friends, always in my prayers.
May we call to mind with gratitude all of the evidence of God's burning charity in our lives today.
St. Valentine, pray for us!