When it comes to keeping intruding gay couples out of the premises of the institution of marriage, there is only one security measure up to the job – the Westminster quadruple lock.

Like many aspects around last week's launch of the bill to introduce equal marriage in England and Wales, this term used to describe the multiple layers of protection that will be afforded the clergy to allow them to act as their beliefs dictate – measures which include a ban on same-sex marriages being conducted by the Church of England and Church of Wales – comes edged with hysteria. Only the paranoid, fearful and homophobic, surely, would seek more than, say, a standard basic lock. Yet two archbishops in the Church of England declared they still wanted to see the "shambolic" gay marriage bill stopped. For them, even the Westminster quadruple lock was not enough.

So, it was a relief when, on Wednesday, the Scottish Government published its draft legislation for our own bill, and there were no strange multi-layered locks and no ban for the Church of Scotland, only talk of allowing churches to opt in or opt out, and protecting both churches and individual celebrants through changes to the Equalities Act.

The tone of the bill suggested that this is not about thrusting gay marriage at a society that doesn't want it, but rather in a wider sense, giving people the opportunity to marry as they wish, in the places they like, to whom they like. Gay marriage is a key element. But it is also about letting people get on with leading the lives they want to lead.

One of the more frequent criticisms levelled against both Westminster and Scottish governments is that both bills will reshape marriage. Archbishop Vincent Nichols of Westminster and Archbishop Peter Smith of Southwark, for instance, last week attacked the UK plan, declaring: "The meaning of marriage matters. The Government has chosen to ignore the views of over 600,000 people who signed a petition calling for the current definition of marriage to stay, and we are told legislation to change the definition of marriage will now come to Parliament."

In the House of Commons, Conservative MP Peter Bone questioned Equality Minister Maria Miller's right to redefine marriage in this way.

What Bone and others fail to acknowledge is that it is not the UK Government, nor any other government that is redefining marriage. Nor is it any church. It is we, the people, over the last half century who have created a marriage revolution. As the American historian Stephanie Coontz puts it in Marriage, A History: How Love Conquered Marriage, we, as a wider society, have changed marriage into a union of love, not power exchange, convenience, or structure in which to divide gender roles.

"Opponents of same-sex marriage," Coontz writes, "worry that allowing two men or two women to wed would radically transform a time-honoured institution. But they're way too late on that front. Marriage has already been radically transformed – in a way that makes gay marriage not only inevitable, but also quite logical."

So when politicians start harping on about the role of marriage in providing stability for children, they miss the point. Happy marriage may be good for children, but that is not why all people enter into it. Mostly they marry because, as the celebrant of a wedding I went to last weekend put it, they want to sing out their love in public.

An editorial last week in the Guardian described how "gay marriage will allow the public realm to catch up" with what is already happening out there in the world – for instance, with the fact that, legally, civil partnerships are akin to marriage, and that couples in such partnerships already often refer to each other as "husband" or "wife". In other words, this final step of legislating for equal marriage is merely symbolic. Those who are panicking are really getting in a tizz about something that has already happened. The horse has already bolted and is frolicking merrily in the marital paddock with a handsome looking same-sex steed.

There are some who accuse the state of attempting to mould our private lives. Their belief is, as Brendan O'Neill writes in the online magazine Spiked, that government is attempting to get a "foot in the door of our private lives and to assume sovereignty over our relationships". But that is not what is happening here. Really, what we are seeing is the state struggling to play catch-up with the realities of individual life choices.

And the knowledge of this revolution is what terrifies many people – particularly the homophobic. This is why there has been such a frenzy of feeling. The anti-gay marriage crusaders see that there are other lives out there already not being lived according to the traditional model, that gay partnerships are on the rise, heterosexual marriages are on the decline and complex multi-layered family structures are common. Often they look to the state to stop this. But actually it is helpless.

Nevertheless, the Church of Scotland and Catholic Church remain opposed, in spite of the reassurances the Scottish bill provides. It is hard to understand what their problem is, given that churches have been given the chance to opt in or out and the equality laws are being strengthened. Except, of course, that this does provide another opportunity for some churchy types to let rip with a full-throttle homophobic rant and remind the rest of society that according to a text written several thousand years ago, homosexuality is sinful.

Here is a fear that generally does not speak its own name. It is not gay marriage, really, that many critics abhor, but gay sex – and I guess if you do have some mystic belief that the Bible is the literal word of God, that position is inevitable. But I wish they would call it for what it is, let's not pretend this is really about marriage.

Scottish Liberal Democrat leader Willie Rennie talked this week of the Scottish bill as "a natural step towards the modern, tolerant and progressive Scotland we all want to see".

In fact, I don't see it as being progressive or modern, but about simply acknowledging what is, acknowledging the way we are. Some minority of us are gay. Many of us are straight. Some of us are gay and want to be married. Some of us are straight and would run from anything involving rings or churches as if it were contaminated with anthrax. Those that object to this as a future are moving with blinkers on. They have not noticed that the change has already happened and is somewhat unstoppable.

Marriage will never again be what they imagine it once was. Whatever kind of lock you put on it now, in the name of love, the institution has already been broken open.