How do you handle it when your friends fight in public?

We can see a monumental argument is brewing. He has become snarky and sarcastic. She is sniping at every opportunity.

And the rest of us – sitting around their dinner table, where we have been invited as their guests – are waiting for it to blow. It’s like a vaguely malevolent old dog, sitting on a back verandah. It might bite soon, it might turn nice for a while and bite later. It’s comfortable in its spot – but it will bite.

As we wait for the inevitable, we fill the room with false laughter and nervous conversation on positive topics, desperate to swing the mood back to benign.

Of course, we know that won't happen. It never does. Instead, we'll be treated to stabs like this:

"How are you going there, lard-arse? Fancy standing up any time soon?"

"Oh, look who's talking. The man who can sit in front of the television for so long he's almost eaten by the chair."

Or this.

"What do you guys think of desert? Not bad, don't you think - if it was made by a six-year-old."

"You'd know - you've got the intellect of one."

Or this.

"God, I hate that shirt."

"Just as well you don't have to wear it then."

"No, but we all have to look at it. Good on you, Calvin Klein."

At this point, one of two things will happen. Someone will say they were only joking. Don't be so sensitive. Oh for god's sake - talk about an overreaction. There will be an extended moment of excruciating silence while neither of them apologise. And then one of the onlookers will say something we hope is soothing, and the rest of us will leap on the topic like a starving man on a buttered crumpet and we'll all pretend everything is just hunky dory.

Or it will flip from sniping into a screaming match. They will be oblivious to anyone else in the room, or the fact we are so uncomfortable we want to just slink quietly behind the lounge then escape through the window into air that is fresh and unpolluted by this bile. And the night will end early and awkwardly, with thankyous for a lovely evening and a lame joke about how at least the food was good.

We will practically run for our cars.

This couple have been together for years, and this scrapping has been a feature of their relationship since day one. To start with, the comments really were made as jokes, and we all laughed because they seemed so happy. But over the years, that has changed, and it has become nasty and destructive. The rest of us talk about it regularly. Mostly, our conversations come down to this: Why the hell are they still together?

We spent a lot of Sundays at our mother-in-law's. Ten adults, 7 kids, it was always a hectic day. The day was also, unfortunately, dictated by the mood of one of the couples. In particular, the mood of my then sister-in-law. If she was in a good mood, the day generally went wonderfully and was enjoyable. If she wasn't - which was often the way - we all tip-toed around her, overcompensated with polite conversation and basically ignored the elephant in the room, which was her undiluted, seething hatred for her husband.

Her silence, his open contempt for her, the palpable fear on their children's faces, it was highly uncomfortable for all of us and I now, in retrospect, don't know or can't understand why we didn't call them out on it. Why one of us didn't ask them just to stay home if they weren't getting along? Said they should have been mature enough to not make everyone else suffer because they were too selfish to work out their issues before they got there or after they got home.

They are divorced now, which is best for everyone.

1. Should I say something?

2. What is this doing to their self esteem?

3. I will never invite them to anything together in future.

4. How could people who call themselves my friends be so unbelievably rude?

5. What level of self-delusion makes this behaviour ok?

6. Does this get worse when we're not here?

7. How can I leave?

It will get to the stage where I'll have to say something. I'll have to live with the fallout, whatever it is. I might lose my friends.

But more than that, I think it's time they lost each other.

Like this? Why not try ...

‘The text that revealed my husband had sex with my friend.’

“The upside of divorce is getting rid of your spouse.”