A few saints get secular recognition, at least by name. Subtract those associated with nations or ethnic groups, and perhaps Valentine, cleric and martyr is one of the very, very few left standing.
While recognizing the importance of those brother-missionaries to Slavic Europe, it may be that the love of two deserves some patronage in the Christian orbit. Or maybe marriage and the commitments associated with it are on firm ground, eh?
Valentine is attributed with blessings Christian marriages the state (Rome) would not accept. Somehow, it strikes me as more seemly that a husband and wife could be designated as patrons of affection. But I can’t foresee that will ever happen. Valentine is pretty well rooted in the profitability of cards, sweets, meals out, and perhaps the occasional household appliance or bit of technology.
Still, red is the color of martyrs. Those of us in long-lasting relationships know the sacrifices needed to maintain and nourish love. Somehow, I don’t think Valentine would look askance on any of that, even if the occasional chocolate got into the mix.
Happy day, everybody.
Catholic Sensibility 
There is the lone example I am aware of of a joint canonized married couple from the early years of the Church is SS Priscilla and Aquila, martyrs (traditionally reckoned in Ephesus), in terms of a canonized married couple who didn’t have some odd Josephite type marriage. Interestingly, their feast in some Orthodox churches is February 13 (Julian). Might be nice to see the category of Spouses and Martyrs in the calendar.