Was last week a great one for sex? Well, that depends. If your taste runs to threesomes then life just got even better. There’s now an app for that: 3nder. After only six months in business it has registered more than 200,000 users.

Life also improved last week for gay couples living in the 11 American states where same-sex marriage became legal. Only 20 more states to go and the country will have finally fulfilled its constitutional mandate to grant equal protection under the law to all citizens of the United States.

Otherwise, I would say that on balance it has been a mixed bag of sexual transgression and religious fundamentalism. Stolen nude photographs of the actress Jennifer Lawrence were shared online; a Texas law closing 80% of the state’s abortion clinics came into effect; and Phil Robertson, the gay-bashing patriarch of the popular TV docudrama Duck Dynasty, issued another fire and brimstone statement about biblical sex versus the rest. And that’s only seven days in the life of a nation.

British attitudes to sex could fill an entire library. But I’m telling you, Americans are all over the place. This is the country, after all, that invented the scarlet letter as well as the celebrity sex tape.

America was founded on paradoxes — the immortal statement in the Declaration of Independence, “All men are created equal”, was a beautiful truth stained in blood by the lie of slavery. Like race, sex has been a jagged fissure running through the country’s history. Ever since the pilgrims landed on Plymouth Rock, America’s claim to a national identity has been distorted by an unending battle over the right to define American values. The reason is that both race and sex were (and remain) microcosms of the larger battle of America and the meaning of freedom.

Put simply, freedom is not natural. Sex is natural. Freedom is at best a social construct and probably just a social contract. Rousseau was right: man is indeed free and everywhere in chains — largely because humans are not psychologically equipped to live in a state of freedom. For the Puritans, starving and shivering during those first harsh winters in New England, the freedom to create their own kingdom of heaven on earth required, perversely, every individual to wear the yoke of moral purity.

Nathaniel Hawthorne’s novel The Scarlet Letter was in part a protest against Victorian hypocrisy, but he drew his inspiration from the 17th-century men and women who suffered at the hands of their Massachusetts brethren. The real model for the book’s protagonist, Hester Prynne, was probably Mary Batchellor, a young woman married to an 80-year-old preacher, Stephen Batchellor.

In 1650 Mary was living apart from her husband when she became pregnant. She was convicted of adultery and sentenced to 39 lashes. The letter A was not merely attached to her clothes but also branded onto her flesh. For good measure, her request for a divorce was denied.

It would be fair to say that Mary Batchellor was made to suffer for the sins of the community. In the 1640s the governor of Plymouth, William Bradford, complained that no amount of punishments could “suppress the breaking out of sundry notorious sins . . . not only incontinency between persons unmarried . . . but some married persons also. But that which is worse, even sodomy and buggery (things fearful to name) have broke forth in this land.”

The practice of whipping and shaming died out in the mid-18th century. As the country lurched towards independence, sex no longer loomed large in the swirling debates about freedom. It would remain a background hum until the conclusion of the civil war in 1865. Then, with the foundations of liberty established, the familiar obsession with persecution, prosecution and sexual purity returned.

The name Anthony Comstock means nothing any more. But towards the end of the 19th century this evil man had his fingers and eyes in every bedroom in America.

By the 1870s there were dozens of contraceptive devices available to purchase. Comstock, a civil war veteran who fought for the anti-slavery north, made it his life’s work to prevent any information about abortion, contraception or the devices themselves from reaching American homes. As head of the New York Society for the Suppression of Vice, he successfully lobbied for the so-called Comstock law, which made it a crime to send anything of a sexual nature via the US postal service.

Comstock’s efforts led to 4,000 prosecutions and the pulping of 160 tons of “vicious” material. Among the seized works were medical texts, art books, contraceptive pamphlets, novels by DH Lawrence and plays by George Bernard Shaw. Comstock labelled Shaw an “Irish smut dealer”. Shaw hit back: “Comstockery is the world’s standing joke at the expense of the United States.”

Unfortunately, the Comstock farce was in earnest. During the course of his career Comstock claimed responsibility for 15 suicides, including that of the pioneer sex therapist Ida Craddock. She killed herself in 1902, the night before the start of a five-year prison term for writing an “obscene” book called The Wedding Night.

In her suicide note Craddock wrote: “Perhaps it may be that in my death more than in my life, the American people may be shocked into investigating the dreadful state of affairs which permits that unctuous sexual hypocrite, Anthony Comstock, to wax fat and arrogant, and to trample upon the liberties of the people.”

Craddock’s wish came true. The Comstock law was eventually repudiated — but not until 1965. The pornification of the marketplace from little girls’ dolls to mainstream music has obscured the fact that sexuality in America remains the last redoubt against the founding promise of liberty and the pursuit of happiness.

It’s hard to believe that adultery is still a crime in 21 states. But the truth is that the ubiquitous presence of sex is not the same as having the freedom to make choices about it. The right to marriage, to contraception and to abortion, these have never been guaranteed and still aren’t. As I said, it was a mixed bag last week.