Complementarity may not be central to all long-term relationships. Filter theory assumes the most satisfying relationships are complementary. Markey and Markey used a sample of lesbian couples who had been romantically involved for more than 4 years and found couples of equal dominance were most satisfied. This suggests that complementarity may not always be associated with long-term satisfaction.
The theory cannot account for relationships which defy the odds: long-distance couples; couples who are diametrically opposed in terms of attitudes; couples who are so alike as to not complement each other; thus it lacks full explanatory power
lack of temporal validity to filter theory due to increase of online dating and contact via dating apps etc which means that demographic similarities is not an issue in relationship formation
