Hi Abhishek! There is no such restriction on solo male travelers in Bhutan. Contrary to popular belief, solo male travelers also do not face any difficulty in obtaining travel permits to Bhutan. If you are doubtful, you can check with the travel agent whose services you are engaging. Happy Travelling!
Solo Indian Male Travellers can travel to Bhutan without an issue. There is no difficulty in obtaining the permits. I also met a few solo men from India while I was in Bhutan. So that shouldn't be a problem.