My wife and I both object to the commercialisation of love and relationships, which is pretty much the reason behind Valentine's Day these days. Like you, my wife and I share a lot together, constantly tell each other how much we love each other, do little things for each other all the time, talk a lot and spend as much time as we can in each other's company. These are the things that keep a love strong, a relationship healthy and the romance alive.
If I might borrow from another season: Valentine's Day - bah humbug!
Incidentally, I think you are neither bitter nor old...