I've never been as inclined as some single people to resent St. Valentine's Day, because I'm happy for those in a relationship they're content with who can use the holiday to celebrate that relationship. But as someone who's never married nor even dated very much, the day used to be something to hide from, an annual in-my-face reminder of that missing piece in my life. Some years, I've even gone media-free for a few days to hide from the commercially-oriented mushiness.
I'm not sure if it's maturity or just resignation, but in my middle years I find that discomfort leaving. For one thing, I'm not sure of my ability to carry off a successful relationship. Sure, I've got some real strengths to bring to a relationship, but I'd bring more than my share of challenges as well. Describing me as 'set in my ways' would be putting it very kindly indeed. Yes, there are things about the single life that are a drag, even scary - but I think I'd rather have no relationship than the wrong one.
I don't know if there's a relationship in my future or not - I may meet someone tomorrow. I'm not too many years from the time when I'll be old enough for what I call a 'friendship marriage' - two older folks who marry after a relatively short engagement and without too much fuss. No grand romance - at least publicly - just a commitment to be there for each other as long as possible.