"What the hell is wrong with you?” a girl recently asked me, her face screwed up with concern and incomprehension. What prompted this question was my admission that I was still unmarried. Sadly, I’m now at the age where I need to have a ready excuse for not having settled down. The excuse that works best with women, I’ve learnt, is to shrug my shoulders and lament that I just haven’t met the right girl yet.

The truth is probably simpler than that and best summed up by the “New York taxi driver” theory. According to this idea, men — like New York taxi drivers — cruise around all day, picking up fares. They carry some for a long time, some for just a short while, without giving it all that much thought. But at a certain point, when they’re tired, maybe bored and have had their fill, the taxi driver decides it’s time to turn off his light and go home. Whoever is in the back of his metaphorical relationship taxi at that point is the one he marries.

It’s an unromantic theory that implies that marriage is more a matter of timing than of magic. But there’s something in it. I know of many relationships — including some of my own — that broke down when the women pushed for commitment, but succeeded only in being pushed out of the taxi. The New York taxi driver theory implies that the clever women are the ones who quietly cling on in there, monopolising the back seat, with the doors firmly locked, until the driver is ready to turn off his meter. Did you ever play pass the parcel as a child? The kids who won were the ones who passed it particularly slowly, maximising their time with the parcel.

Men don’t like to admit it, but we talk about relationships every bit as much as women. Especially as we get older. We don’t discuss them like women do: with wisdom and familiarity. Men discuss relationships like monkeys trying to decipher sheet music.One of the main themes of our analysis is: how do you know if she’s The One? What has emerged in my research is that “when” is every bit as important as “who”. This was illuminated the other night when a friend, after a few glasses of wine, confided in me: “If I’d met my wife even a year before I did, there’s no way I would have married her.” It’s not that he doesn’t love her. It’s just that, at that time, he simply wasn’t ready to settle down.

My married male friends broadly fall into two camps. The first is full of men who boldly state: “You know when you know.” My (absurdly happily married) brother falls into this camp. When discussing with him the possibility of my marrying a now ex-girlfriend, he said: “If you have to think that hard about it, it’s probably not right.” The romantic in all of us wants to believe this to be true.

The other school of thought was best summed up by a married friend (on the guarantee of anonymity). “Was I nervous about marrying her?” he asked. “It was like stepping off the edge of a 1,000ft cliff and hoping a barge full of feather pillows happened to be passing below.” I think this is the more realistic school of thought. This doesn’t mean that the “you know when you know” camp are all liars. Not all of them. Just a lot of them. They’ve made the leap and it’s in their best interest to make it seem more poetic than it was. The most honest ones said: “It was just timing.”

I don’t want to believe the New York taxi driver theory, because I’m a romantic. I want my heart to ache and my insides to churn. I want to feel an irrational, inexplicable yearning. I want to experience a star-of-Bethlehem moment when I meet The One. I still believe that falling in love should be an involuntary reaction . . . like the gag mechanism. Unfortunately, the older I get, the more I think there may be something in the New York taxi driver theory. At a certain point, does the marriage decision become transactional rather than emotional?

With the benefit of hindsight, I’d say there have been five women in my past who would have made great wives/mothers and who also indicated they were interested in the position. Probably more than I deserve. So, how is it that I’m still single? I guess the timing wasn’t right — that, or they pushed me for an answer and, like many men, my default response when under pressure is a cautious “no”.

The good news, according to the theory, is that at least men are like New York taxi drivers. If they were like London taxi drivers, they would just stop, roll down their window, find out where you wanted to go, decide it’s out of their way and drive off. Or if they were like Paris taxi drivers, they would pick you up, but not know how to get to your destination and you would have to hold your breath for the duration. Or if they were like Rome taxi drivers, they would get you where you wanted to go, but scare the hell out of you along the way by driving like Lewis Hamilton on crack.

I guess I should be flattered that people feel they can come right out and ask me why I’ve never been married. At the very least, it means that there’s nothing obviously wrong with me. If I were missing half my face or could move only with the assistance of a crane or had halitosis that would melt a candle at a hundred yards, they wouldn’t ask. When people stop asking, that’s when I’ll be really worried.