Classes are normally the last thing on a couple’s minds as they race towards their big day, with the emotional highs as well as all the endless practical to-do lists. But most rabbis insist couples enrol for a series of sessions to teach them about married life in Jewish tradition.

The main focus of these classes is a set of regulations concerning “family purity”, which govern when husband and wife are expected by halachah to abstain from sex around the menstrual cycle.

The bride and groom traditionally study separately and the classes tend to cover the rules, often supplemented by some relationship advice and maybe insights on husband-wife intimacy. But there is a quiet change taking place, as interest in sex therapy and related fields grows within orthodox communities.

Two years ago in America, the first co-educational chatan and kallah teacher-training (CKTT) workshop took place. The four-day conference set out to train orthodox men and women who teach bride-and-groom classes — often rabbis and rebbetzins — to also be sex educators.

The organisers of this conference, from the Orthodox Feminist Alliance, Yeshivat Maharat and Yeshivat Chovevei Torah Rabbinical School, certainly tapped into a demand, as there were four applicants for every place. The discussions, according to accounts published in the Jewish Week of New York at the time, appeared to be far more explicit than orthodox communities are accustomed to and addressed in detail topics often glossed over, including “candid discussions about the first night”.

This development is on the left edge of orthodoxy but in the Charedi world there is a growing acceptance of more explicit talk about of sexual matters. It is five years since two authors released The Newlywed’s Guide to Physical Intimacy, which caters especially for ultra-orthodox standards and it has sold well — and been translated to Hebrew.

It limits itself to sexual acts permitted by Jewish law and respects the most modest of readers by making diagrams an optional extra, in a closed envelope at the back of the book. And so, while Charedi bride and groom classes are not being overhauled, more people are turning to literature to initiate themselves into the more explicitly sexual matters.

In a connected development, in at least some parts of the Charedi world there is growing openness to therapy. Bat Sheva Marcus, the same sex therapist who helped lead the event run by the Orthodox Feminist Alliance and its partners has a patient list that is one fifth Charedi. One Charedi rabbi, who started referring women to her around seven years ago, told The New York Times that she is “like an Einstein in our days”.