To explore the relationships among fertility stress, dyadic coping and marital quality in couples undergoing in vitro fertilization‐embryo transfer (IVF‐ET). Couples receiving IVF‐ET treatment at the clinic of the reproductive medicine centre of a hospital in China from February 2023 to October 2023 were selected by convenience sampling. A general information questionnaire, the Infertility Fertility Stress Scale (COMP‐FPSS‐SF), the dyadic coping inventory, and the marital adjustment test were used to evaluate the results. AMOS24.0 software was used to construct an actor‐partner interdependence model that extended to mediation to analyze the relationships among couples' fertility stress, dyadic coping, and marital quality. The fertility stress level of IVF‐ET wives was significantly higher than that of their husbands (p < 0.05). Wives' levels of dyadic coping and marital quality were significantly lower than those of husbands (p < 0.05). Fertility stress, dyadic coping, and marital quality were positively correlated between IVF‐ET couples (p < 0.01). In terms of the actor effect, the fertility stress of IVF‐ET couples had a significant impact on their marital quality through their dyadic coping (β = −0.188, p < 0.05; β = −0.109, p < 0.05). In terms of partner effects, wives' fertility stress significantly affected their husbands' marital quality through their own or their husbands' dyadic coping (β = −0.055, p < 0.01; β = 0.157, p < 0.01). Dyadic coping mediates the relationship between fertility stress and marital quality in IVF‐ET couples. Nurses can use husbands and wives as central individuals and dyadic coping as the starting point to formulate intervention measures to reduce fertility stress and improve marital quality.