A skyload of sunlight floods our bedroom when I open the curtains. R is dozing, and I creep back into bed next to him, wishing I was able to sleep past 7am. The boys are downstairs watching Saturday morning TV, and our eldest is still having an adolescent lie-in that will probably last until midday. R and I have time. These mornings are golden for a couple with young children: the serene quiet moments where sex – the type that was relegated to the evenings long ago – is something I can actually imagine us having in the morning once again.

Propped up with pillows, I read an article about mindfulness on the laptop, and although the word and notion fills me with pessimism and scepticism (anything that requires too much thought can be tedious and doesn't seem to allow any room for spontaneity and healthy stress), I feel for once that I might actually be doing some things right. I am trying to live in the here and now; I'm staying focused on the present rather than lamenting the past too much. What lies ahead is stuff I can loosely plan for, but I'm not fixating about stuff I can't predict with glass-half-full visions of the future.

And then, with the feeling of smug warmth in my stomach that only an article on mindfulness can elicit, I go and ruin it all. God knows I can zap all the good and calm out of a situation with a few choice, ill-timed words.

Just like that. At about the time that R starts to wake, when he picks up his warm, sleepy hand and takes it to the inside of my thigh, I set about destroying the possibility of anything loving at all. The corner of my eye catches a paper bag. It's a fancy one, the type you might think twice about putting out with the recycling.

He's been shopping.

"What's in the bag?" I say, lazily.

"Socks," he says, still stroking my thigh and nuzzling his head into my chest. He is the king of socks. They're sprouting out of his drawers like stubborn weeds. He's like the poor man's 50 Cent, who demands a box-fresh pair of trainers everyday.

"More socks?" I say. "Surprised you have the money. Those aren't cheap socks, you know."

"Give it a break."

And if you could hear yourself now, I say to myself, digging my nails into the thigh that has very suddenly stopped being stroked by R's hand. I'm thinking desperately about how to revoke every mad, crazy word I've said. If you could hear yourself banging on about something as inane as bloody socks, on a morning that was, for a while, cloaked in bliss, then you would certainly stop right now.

But I continue to pick the scab.

"And you eat lunch out every day at work. Do you know how much that costs?"

"Oh do shut up."

And I do, because he is right. I am being despicable, nitpicky, mean, no fun. But I am seething, still, mainly because I don't know why I behave like such an idiot. What it seems like he's said by the way I've reacted is this: "Darling, I've just spent all of my month's salary on drugs, booze and horse-racing and we have no money to pay the mortgage."

What I think I want is for R to say that he is a responsible person who is not going to buy anything for months, and he'll pay back his debts and hand over all responsibility to me.

But then I think of myself, and my genuine fear of money, and my penchant for good coffee and two-for-one deals on moisturiser that promises to make my skin dewy and delicious, and I think, please, be quiet.

It's too late, of course. Our bodies lie on the bed like distant islands at sea; only seconds ago it seemed we could be a happy empire.

"We have one therapy session left. I want you to mention this. Once it was all about drink, and how you tried to control me. Now you want to know everything about money."

But all I can think of is how sorry I am, and how – although money is something we need to discuss – this sort of talk is ridiculous and controlling. Most of all, I feel sorry about the fact that I couldn't wait until after we'd had sex to mention the socks.