I agree, it does depend on how long you two have been together. If its only been a few months. Take your time and enjoy each other. But too long can bread complecence and he will feel like "Why buy the cow when you..." well you know the rest.
So, don't be too vage, be direct. He is either going to stay with you now, or not. And if not let him go. Don't waste your time with some one that is going to slow walk you into what my be years. If you hold on to some one who is not willing to make the next step in a relationship, he may be blocking the one who is willing to comemitt to you completely.
And always pray 