I actually hear this question a lot. Before I address the question directly, let me make one point. When it comes to a person wearing glasses or corrective lenses or contacts... who really wants something on your face or in your eyes? I don't think anybody does. But, people tolerate glasses and contacts because it makes the quality of life much better. The quality I speak of is vision of course. So, with CPAP, I tolerate it because it makes my sleep better which in turn makes me happier in many ways. So, once you get glasses, you probably need them for the rest of your life. Now, back to the original question.
Will I have to wear CPAP forever? The answer is...it depends. There are three general categories people fall into that use CPAP: airway architecture, large tonsils, and obesity.
Some people need CPAP because the architecture of their airway is constricted. This can be genetic in that is how you are "designed" or the genetic material inherited from your parents determined your airway size. A simpler way to look at it is some people are tall. Some people have small hands. Some people have bigger airways and some people have smaller airways. If somebody falls into this category, most likely you should use CPAP for the rest of your life.
Another category for constricted airways is large tonsils. Most likely this category of CPAP user will have to use CPAP for the rest of his or her life unless you have surgery to remove your tonsils. Removal of the tonsils is not a guarantee to get off of CPAP.
The last category of CPAP users is obesity. Most people on CPAP fall into this category. When a person gains weight, his neck becomes thicker or weight is gained beneath the chin. Weight is gained in other areas of the body too of course. But, when the neck and face become thicker, that adds to the constriction of the airway causing sleep apnea in some people. What actually is happening is more complicated than this but for our purposes I'll leave it at that. So, people gain weight and people lose weight. When you lose weight, some of that weight is taken off of your airway. So, theoretically, you can lose enough weight to get off of CPAP. I have been doing sleep studies on people for 10 years now and I've only seen 1 person able to do this. But don't let that burst your bubble. There is probably others that have done it, they either just don't come back to get re-tested or go to another sleep lab...or the possibilities go on.
In general, once you are on CPAP, most likely you will need it indefinitely. But, don't let that deter you from trying to lose weight or maybe even getting surgery. When it comes to surgery, there are some caviots which I may touch on later if there is interest. I hope this helps!