I have no clue, but I would say you need toleave it alone, and enjoy your relationship with him as it is. He obvisouly knows what you want, but if he isn't ready, he isn't ready. You made your point in the initial email and he wanted to give you a present.
That is nice and kind and sweet, so I would wear it in my right hand and enjoy my present. I am a firm believer that if he wants to, he will. Not all men want to discuss these things, and that does not mean he doesn't love you or want to marry you ONE DAY... Maybe it just means he doesn't want to now, or maybe he does want to control it and do it on his terms and be more traditional.
Either way, I think you should just enjoy what you have with him, until you can't anymore.