When I was in high school, we read C.S. Lewis' The Four Loves, for our Marriage and Family Living Class. The text was mostly a philosophy of love, with some theology thrown in here and there. Lewis would suggest that love could be summarized in four areas, Affection, Charity, Friendship, and Eros. In the human person these directions complimented each other in our relationship with one another. First of all we come to know these 'types' of love from God who is all love and all being.
Today as we celebrate St. Valentine, we acknowledge our own love relationships. Boyfriends and girlfriends will be sending cute notes and gifts to each other, and husbands and wives will re-affirm their affection for each other. While we know very little about the real Saint Valentine, we do know that he is categorized as a martyr. So he died for the faith which he professed.
The aforementioned love relationships which we have with each other all demand a dying to oneself in order to be actualized. We talk to engaged couples about this a lot. In order for ones relationship to flourish and become life giving, it has to reflect the Paschal Mystery. There was a car commercial some time ago which celebrated the fact that their new van had personal entertainment for each occupant of the vehicle. So no one would have to communicate with each other, and accordingly the trip would be more enjoyable.
Of course such examples do not mention that relationships would not be built, nurtured, or nourished. Love can never be reduced to the weekday afternoon kissy-face drama, whereas the characters have the depth of a finger bowl. Real love is messy and offers an ongoing relationship of suffering, dying, and rising. The failure to thrive designation is what probably kills most of our relationships.
The four loves begins when we are created, and continues all of our lives. Like the martyr Valentine, we understand that the cross is a sign and symbol of love.