This study models associations among intimacy, relational uncertainty, partner interference, relational turmoil, and topic avoidance in Korean and American romantic relationships. We surveyed 294 individuals from the United States (N = 156) and South Korea (N = 138). The American model indicated that intimacy was negatively associated with relational uncertainty and curvilinearly associated with partner interference, relational uncertainty was positively associated with topic avoidance, and partner interference was positively associated with perceived turmoil. The South Korean model revealed that intimacy was negatively associated with relational uncertainty, while both relational uncertainty and partner interference were positively associated with perceived turmoil, which was positively associated with topic avoidance. Although the American and Korean models were statistically invariant, some notable cultural differences are discussed.