1) yes you have right to visit public beaches . you cannot be restrained from visiting public beaches merely because you are a bachelor .
2) the best option for you is to raise the issue in media as to how bachelors are being denied access to public beaches .
3) also address letter to Muncipal commissioner in your city regarding discrimination against bachelors
4) file an RTI application as to whether any policy decision has been taken to deny access to bachelors in kovalam beach