Aim
This current RCT aimed to test if couples who have benefitted from two MCs can maintain and boost their relationship functioning with a third MC provided at Year 5. Using a sample of responder couples, we target this aim with three main analyses of (1) the long‐term maintained effects of the two previous MCs prior to the current baseline, (2) the between‐ and within‐group booster effects of the third MC using the current baseline, and, finally, (3) the between‐ and within‐group booster effects of the third MC using the original baseline in the previous RCT in order to graph the outcome variables across the full study period of 5 years and 3 months.