The goal of this sequential multiple assignment randomized trial is to conduct a preliminary evaluation of Our Love, Our Style (OLOS), a web-based sexuality and relationship education program for autistic young adults in South Korea. This study aims to develop a tailored sex and relationship education model for autistic adults in collaboration with autistic adult research partners by employing a community-based participatory research (CBPR) approach, and to progressively evaluate and expand the effectiveness of an adaptive intervention that reflects individual learner characteristics using a sequential multiple assignment randomized trial (SMART) design. Through this process, the study seeks to strengthen the sexual health and relationship-building capacities of autistic adults and, ultimately, to promote greater independence, improved quality of life, enhanced autonomy, and social inclusion in South Korea.

Participants will be randomly assigned to one of the two initial groups; the web-based learning group vs. the web-based learning and coaching group. During the first-stage intervention (4 weeks), the web-based learning group engages in individual learning through the sex and relationship education web portal developed in Year 1, while the web-based plus group-coaching group participates in both web-based learning and small-group sessions.

Following the completion of the first-stage intervention, an interim assessment is conducted to evaluate learners' responses, and participants are classified as responders or non-responders according to their quiz performance within the program. Responders maintain the original intervention, whereas non-responders receive an additional, more intensive intervention.

In the second-stage intervention, non-responders in the web-based learning group receive an additional group-coaching component (web-based → web-based + group coaching), whereas non-responders in the web-based plus group-coaching group receive additional individual coaching to provide more intensive learning support (web-based + group coaching → web-based + group coaching + individual coaching). For non-responders, both group coaching and individual coaching are provided either via Zoom or in person according to participant preference, with each session lasting approximately 60 minutes. The intensive learning intervention incorporates more concrete and realistic examples and uses strategies such as modeling, role-play, and quizzes, which are difficult to implement in a web-based format alone, in order to enhance learning effectiveness through real-time interaction and positive reinforcement.

To assess the durability of the intervention effects, pre-intervention, post-intervention, and follow-up assessment outcomes will be compared and analyzed using the evaluation measures to examine the retention of sexual knowledge, changes in relationship-building abilities, and improvements in social skills. Additionally, mental health and quality of life will be examined through supplementary assessment tools. This will allow for a broader understanding of the overall effectiveness and potential benefits of the sex and relationship intervention, as well as an in-depth evaluation of its impact across multiple domains of participants' lives.