"You must let me pay for this!" says My Canadian Girlfriend as we're walking towards a swanky Manchester gastro-pub for our Sunday Lunch, "You pay for everything."

"You paid for lunch yesterday and even though this is going to be a fully cooked meal, it'll be just as expensive as coffee and a Sandwich at Starbucks. And you paid for the Family Guy DVDs for me to give to your sister for her Birthday - although I suppose technically, since we watched them before wrapping them up we're not exactly in a position to take any moral high ground on those."

"And", I chirp up helpfully "don't forget about that time you saw me make eye contact with another woman on the Tram - you said I'd pay for that too...."

The air turns cold and there's an icy silence.

Personally, I don't see the problem with it. Since I was born with a penis, I am automatically entitled to earn 16% more than her for the same job. I can see it now, God is stood with Adam and Eve - "Right I have a couple of things to give out - Which one of you wants to earn the most money? Adam's hand went up first - which means Eve, let's have a look at what you could've won.... Its a speed boat! I suppose the only consolation is that you can now have the next thing - multiple orgasms."

"Ok," I say reluctantly, "you can pay for this."

Now I'm going to let you into the deeper depths of the male psyche here. This is a regular heated discussion we have, either on the way to Sainsburys, in the car park of Sainsburys or while getting a trolley in Sainsburys, and I have a system to solve it that works every time. Normally, I'll simply agree to let her pay and then wait the 20 minutes or so it takes to get the shopping and then when we reach the checkout, I just get my card out and pay. I'm not saying it's a very clever system or a well thought through solution with graphs and a PowerPoint presentation. But it is effective.

"And don't think you're doing that stupid thing where you agree to let me pay then pay yourself!" she replies.

Damn she's worked out the system. If the system is no longer sacred then what is? Next she'll figure out that I only read her Glamour to get practical relationship advice and not look at the models and celebs.

So we enjoy a nice lunch, she has the fish and chips, I have the curried chicken sandwich and fat-chips. We spend time putting the world to rights, discussing the week ahead and pondering why the skinny waitress is trying her hardest to make herself look as fat as possible.

And then the bill arrives. It takes all my will power not to get my Maestro card out. My Canadian Girlfriend furtles around in her bottomless handbag. She removes an umbrella, Lip Gloss, more pill bottles than Lloyds Pharmacy, a single unwrapped extra strong mint and a copy of the Treaty of Rome.

"Erm," she says looking up, "I think I've left my wallet in my coat. Is there any chance you could cover this?"