SO there you are, sitting on opposite sides of the living room to your partner, barely speaking, eating dinner in front of the TV. And finally you just say it: "I want a divorce." You almost broke up once, but it didn't quite happen. They made so many promises that you gave it another whirl. Over the last few years, though, the relationship has just gone from bad to worse.

But what do you get in response when you say the relationship is over, that you want out? Either stony silence, shouted insults, or "No, you're not leaving". What sort of marriage is this? What sort of union? You can't keep someone prisoner in a marriage they don't want. You can't force someone into a union.

That's essentially the metaphorical relationship between the Yes movement and unionism, today. Don't misread the symbolism: this isn't about Scotland and England – countries don't hold positions, political organisations do. This is about the Yes movement, as represented primarily by the SNP and Greens; and unionism, as represented by Tories, Labour and LibDems. Broadly, we're talking a 50-50 split across Scotland between the two positions, between Yes and No.

So, we've half of the nation asking for change, wanting a way out of a relationship they can't stand any more; and the other half, simply refusing to even talk about divorce.

Unhealthy? If you knew this couple, you'd recommend intensive therapy.

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But here's the thing: to extend the metaphor, one half of the couple – the one who wants to leave – has a whole load of ideas about what they want to do with their life. They've looked at the past and decided it's not worth saving; they've looked at the present and deemed it a mess; and they've thought about the future – they just don't want to spend the rest of their life in a relationship that's dead to them.

The other half of the couple – the one who wants to keep their old love trapped in a dead marriage – has nothing to offer. Ask them about the marriage and how they can make it better and they've zero ideas. Sometimes, they even sneer at the marriage: the marriage they want to keep their partner locked into. It's all about them. There's no give, no take. The only refrain is: we're staying married whether you like it or not.

Unhealthy? If you saw a relationship like that, you'd call it abusive.

Now, I'm open about my support for independence. I reckon readers are also aware that I can be a rather fierce critic of my own "side". That's important in this age of partisan idiocy. If you can't hold your own side to account, then you're part of the problem.

Last week, I made clear I wasn't massively enamoured of the SNP's route map to independence. It's messy and convoluted, and I don't like the idea of this "de facto" referendum at another General Election. It's presumptuous and risks backfiring dreadfully. I've also been rather critical of the current independence prospectus. It does little, if anything, to persuade undecideds. And if an independence campaign is about anything it's about persuading undecideds, not preaching to the choir so the Yes movement feels good about itself, or the SNP keeps its polling numbers boosted with endless "indy is coming" bait.

That said, though: at least the Yes movement is talking. At least it's coming up with ideas, good or otherwise; at least it has a notion of where it wants to go.

Unionism sits like a fat slob in the corner, while its erstwhile lover goes to the gym, gets a new wardrobe, finds new friends, and just, inevitably, drifts away. For who wants to stay with an angry, sullen lump?

If unionism was worth tuppence, its representatives would be up on their feet shouting from the rooftops about how amazing the union is – but unionism has nothing to say, nothing to offer, and unionists know that: their political position is a black hole.

All unionism has to offer is insults: independence is stupid; you'll all starve; you'll be poor. Very like a controlling partner.

Maybe independence is stupid, but what exactly is the Union offering now except poverty, hunger and stupidity?

If your only way of winning an argument is to insult your opponent, you've lost already. If your only way of keeping a relationship together is to say "no, you're not leaving me", then you're a bit of a psychopath.

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The Union offers nothing. It's a dead ideology, too dumb to know to lie down, get into its grave and pull the earth over it.

Sure, there's every chance that unionists will get their way this time. Dogmatic, abusive people often do win out … for a while. It's likely the SNP will be defeated at the Supreme Court; it's also a hell of a task to try and get 50% of votes at another election.

So sure, maybe the Yes movement will face disappointment and be forced, like a bullied spouse, to remain in an unhappy marriage, for a while longer.

But the more unionists just shout and say no, the more the Union shows itself to be empty with nothing new to offer, the more the Union represents a political status quo in Westminster that isn't just antithetical to the lives of ordinary people but downright dangerous, then the more support for independence will grow.

The reason unionists have nothing to say is because in their hearts they know the Union is a void. They simply can't accept that hard truth, or the fact that anyone could want to leave. Narcissistic much?

One day unionists will wake up and realise they've blown it. They could have saved the marriage if they tried. But they slobbed it. They were just angry, nasty, abusive. If you care about a relationship you work to fix it. You don't say "no" to your partner when they want to leave, you don't stand blocking the front door like a thug. You offer some hope, you come up with ideas for a better future together. You listen and try to compromise. If you don't, you deserve to be alone.

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