Saying you can't wait forever, and NOT saying that you will never file might be effective. The latest he knows is that you would never file, so he has no motivation to resolve anything. He can just keep floating along, and knows you will always be there, if he can't find Miss Right somewhere else.
But, on the other hand, it is a risky step to take, I don't get the feeling that he will react well to that kind of pressure, even if it isn't focused.
And without thinking too hard, I expect there are three or four other, other hands!
