Metrics are an important technique in quantifying desirable software and software development characteristics of aspect oriented software development (AOSD). Theoretical and empirical validation of metrics and of their relation to software attributes is a cumbersome and long process. It is of paramount importance that we validate the utility of metrics we use in order to enable others to use them, too. Aspect oriented programming is an efficient approach to improve the software program at the time of software maintenance for modularizing crosscutting concerns. However, in order to take the advantages of AOP, there is a need for supporting the systematic refactoring of crosscutting concerns to aspects. This paper presents a new cognitive complexity metric namely Cognitive Weighted Number of Children for measuring coupling in Aspect Oriented Software.