Despite the recent emphasis on acceptance in romantic relationships, no validated measure of relationship acceptance presently exists. To fill this gap, the 20-item Frequency and Acceptability of Partner Behavior Inventory (FAPBI; A. Christensen & N. S. Jacobson, 1997) was created to assess separately the acceptability and frequency of both positive and negative relationship behaviors. Data from 12,752 community individuals, 415 community couples, and 134 couples seeking marital therapy indicated that the FAPBI comprises four factors: Affection, Closeness, Demand, and Violation. These factors were consistent across gender, relationship type, and sexual orientation. Furthermore, the factors were internally consistent, correlated with relationship satisfaction, and differentiated couples seeking marital therapy from non-distressed couples in the community.