never-married people and happiness

I recently read a study that found that never married period age 40 an up have higher levels of self sufficiency and can be happier than their married counterparts. I am not forty, but I have never been married as well, and sometimes when I look at my colleagues and associates in my age group who are married( thirties) it does seem like they're not so happy with their life. I am completely happy with my life and being single. I am extremely independent and I sometimes feel that having a husband would interfere with that independence. In short, marriage is not for everyone. What do you think?