How Long Should You Wait for a Proposal?

There is no question in your mind that you are ready to commit to your partner for life. Your partner, howevever, continues to drag his feet. As hard as it is to accept, sometimes relationships outlast their shelf life and stop moving forward. How can you know if your relationship has reached that point, and you have entered that zone of just wasting your time? Is there anything you can do or are you destined to be taken along for the ride?