STUDY QUESTION: Can we develop a web-based sex education programme (programme running in a web browser) that addresses the needs of subfertile couples who are advised expectant management for at least 6 months? SUMMARY ANSWER: The 'Pleasure & Pregnancy' programme addresses couples' needs, is likely to improve couples' sexual functioning, and is subsequently hypothesised to improve the chance of natural pregnancy. WHAT IS KNOWN ALREADY: According to professional guidelines (e.g. the Netherlands and UK) couples with unexplained subfertility and a good chance of natural pregnancy, should be advised at least 6 months of expectant management. Adherence to expectant management is challenging as couples and gynaecologist prefer a more active approach. Targeting sexuality may be useful as subfertility is a risk factor for decreased sexual functioning. STUDY DESIGN, SIZE, DURATION: A novel programme was developed according to the three steps of the Medical Research Councils' (MRC) framework. First, relevant literature was explored. Second, an interdisciplinary expert panel developed a theory (based on a systematic literature review and patient interviews) on how the chance of natural conception can be improved. Third, the expected process and outcomes were modelled. PARTICIPANTS/MATERIALS, SETTING, METHODS: Two licenced clinical sexologists, two gynaecologists, a clinical embryologist and two midwife-researchers, all from Belgium and the Netherlands, proposed components for the sex education programme. PubMed was searched systematically for randomised controlled trials (RCTs) evaluating the proposed components in different patient populations. The needs of 12 heterosexual Dutch or Belgian couples who were advised expectant management were explored with in-depth interviews. The content and delivery characteristics of the novel programme were described in detail with the aid of 'Intervention Taxonomy'. To model the outcomes, a protocol for an RCT was designed, registered and submitted for publication. MAIN RESULTS AND THE ROLE OF CHANCE: To help maintain or improve sexual functioning, mainly pleasure, and hence increase pregnancy rates, the web-based Pleasure & Pregnancy programme contains a combination of psychosexual education and couple communication, mindfulness and sensate focus exercises. Information on the biology of conception and interaction with fertility clinic staff and peers were added based on couples' needs to increase potential acceptability. LIMITATIONS AND REASON FOR CAUTION: This paper outlines the development phase of a sex education programme according to the MRC-framework. Whether the Pleasure & Pregnancy programme actually is acceptable, improves sexual functioning, increases pregnancy rates and is cost-effective remains to be determined. WIDER IMPLICATIONS OF THE FINDINGS: No previous interactive web-based sex education programme has aimed to increase the natural pregnancy rate of subfertile couples by targeting their sexual pleasure. The Pleasure & Pregnancy programme addresses couples' needs and its effect on sexual functioning and pregnancy rate is plausible but remains to be demonstrated by an RCT which is currently ongoing.