Objective: Building on previous analysis conducted by Schober (2012), we explore how paternal involvement in different childcare and housework tasks affect the probability of relationship breakdown between parents. Methods: We use logistic regression on the UK’s Millennium Cohort Study to predict parental relationship breakdown from nine months to seven years post-childbirth. Paternal involvement in four childcare and three housework tasks during the first year of parenthood are used as explanatory variables. Results: The amount of time the father spends alone, caring for the baby during the first year of parenthood is associated with the stability of the parental relationship but the effect of involvement in other tasks is moderated by ethnicity and the mother’s employment status. Conclusion: These non-linear relationships suggest further research is needed to explore the different associations between paternal involvement in childcare and housework and relationship breakdown, which are complex and variable according to different characteristics.