How to double your age in a single afternoon

On the days when I'm ‘working at home’ I get a glimpse into the secret life that R and E lead during the week while I’m not around.

Each Thursday it’s mums of steel, a frightening sounding exercise class at the recreation ground down the road. It’s also the day of Granny’s regular visit.

I’m disappointed to discover that the babies are not used as weights, but glad to spend the time with E while R is exercising. On a break from work, she and I head for the swings while R tones those muscles.

I haven’t met any of the mums of steel before, so I don’t know whether they know about me. Or more precisely, whether they know about the whole two mummies thing. But now I'm going to find out.

‘This is my partner’ R says, introducing me to a particularly steely-looking mum, who is doing stretches while balancing a baby on her hip. She says hello, smiles and quickly resumes the conversation about marathon running.

But she keeps shooting me strange little glances as I sit on the grass playing with E. Well, I reason, maybe she’s never met a lesbian mum before. We’re a fairly rare species, so it’s important to get a good look.

After a while E and I wander home, to find Granny chopping firewood. If this sounds more Little House on the Prairie than home counties suburbia, it’s because my mother-in-law would have made an excellent pioneer settler. She has already painted our front door, cleaned out the garage and made several trips to the dump this morning. One day I expect to return home to find she’s built an extension to the house or dug a swimming pool in the garden.

R bursts in, more sweaty than steely, and explains, laughing, what those strange glances were all about.

It turns out that the steely woman thought that I was R’s mother. At the start of the class, R had explained to the group that her partner and her mother were looking after the baby today. A partner must be a male partner. This woman had leapt to the obvious conclusion – I must be R’s mother.

I am 31. R is four years older than me. ‘She was amazed at how young you looked,’ R reassures me with a giggle. But I wonder whether perhaps I should start thinking about an exercise class too…