The COVID-19 pandemic has seriously impacted the management and trajectory of same-sex relationships. This study considered the mediational role of same-sex partners’ conflict avoidance and the moderating roles of individual and contextual vulnerability factors in the face of the pandemic. Results showed that greater adverse daily life impacts and higher perceived threat of COVID-19 predicted more complaint avoidance, which in turn predicted lower relationship satisfaction and higher anxiety, depression, and substance use. Being a person of color and having higher internalized homophobia exacerbated the pandemic’s negative effects on relationship satisfaction. While moving in with partners during the pandemic was related to more complaint avoidance, lower relational satisfaction, higher relationship termination intentions, and greater mental health risks, it also buffered the negative effects of the pandemic on relational well-being. Same-sex couples are encouraged to constructively solve relational issues and actively discuss moving in decisions. More efforts should be devoted to understanding multiple pandemic-related stressors facing same-sex couples.