The best I can manage is having seen George Best playing football live - just once, and in the company of about 40,000 other people. But Ginny was there, with only a handful of others, boogie-ing the night away under a glitter-ball with Bobby, whom I fondly imagine flicking that long lick of hair back into place across his shiny pate every time his struttings shifted it out of position. (It's probably a good thing that Ginny does not make the same boast of Best: I don't think George ever bothered to dance with girls...)
Most of the time, it must be said, Ginny and I have broadly similar tastes and interests, which is pretty useful to any two people who intend to live together for any length of time. But we diverge when it comes to sport. There is only one sporting moment which grabs Ginny's attention, and it comes when some male exemplar bursts into tears in public - Gazza springs to mind, and Kim Hughes, a cricketer who wept buckets when he was sacked as captain of Australia. What attracts her is seeing the hard, aggressive masculinity projected by sporting icons dissolve in those salty tears; tough men are instantly reduced to little boys.
The sporting divide exists even when we attempt to do sport together. One of the advantages of a freelance lifestyle is that, on a Monday morning, we can set off together for the gym. But once there, Ginny heads into an aerobics class with 30 other women, while I am dispatched to the weights room to pump iron with the boys. I have tried to persuade Ginny that a gentle trot in the park would do just as much good, but she's not convinced: besides, she feels self-conscious about running in public.
But what could make you more self-conscious, I counter, than dressing up in a swimsuit and leggings and bouncing around to music in a bright- lit room, with every bulge reflected in the floor-to-ceiling mirrors? I know from snippets of conversation that emerge that the participants do all monitor each other in detail - but perhaps this is the point.
For Ginny, running around the park feels like doing sport. Going to aerobics, on the other hand, feels like a bunch of fourth-formers bopping around to Top of the Pops, without the distraction of boys. It's a social experience: Ginny has a whole alternative network of gym friends and emerges from the class with a soap-opera of incident and gossip to recount.
This week, the fourth-formers are in open rebellion. The new instructor insists on treating them like infants, dividing the room in two and forcing each half to chorus "Boof, boof" "Woof, woof" in turn, and then "wheeeee" together in time to the music.
Were men actually barred from this class, I asked. No, Ginny said, the occasional brave soul turns up. "But they never come back," she added with a sinister chuckle.
Ginny and I did once attend an aerobics class together. In the early Eighties, at the end of a trip across America, we found ourselves in Los Angeles, where aerobics had just become fashionable. We attended a class with 100 of the hippest Angelinos, disco music blaring, the instructor ordering "Squeeze those buns". I couldn't walk comfortably for a week afterwards, and have never been to an aerobics session since.
But it is not that memory which keeps me out of the aerobics gym at the Balham Leisure Centre. It is pure, unalloyed fear of the fourth-form girls. And what would happen if I burst into tears?