My boyfriend of 2 and half years won't tell his parents about me?

I have been dating my boyfriend for 2 and a half years. Before that we were best friends, so in total I have known him for 9 years. His parents know me as his friend, but my family regards him as a son. We are from two completly different cultures and religons and I have to say that my family is open minded and accepting where as his family is not. I understand why it has been difficult for him to tell his parents about me but it has been over two years now. We talk about marrieage and our future all the time and I know that he loves me. However, it hurts that he is part of my family but I am not part of his. Whats worse is that he is an only male child in an indian family so his parents, especailly his mother are really overbearing. We have disscussed this topic many times and he knows how much it hurts me and much it would mean to me. Yet he still has done nothing about it. What should I do?