i believe you actually are wasting both your time..if the things are as you mentioned, then it is very less likely that you two would want to end up together. at least from your side, you know that you are not going to be satisfied with him.i dont think cheating on him is the best option.you will be better off with a clear break up.
i think you should indeed move on.and you should not think that it was a fault of yours.it was not.what has happened now is a very natural thing.
but the next time,dont choose to be with someone just because the sex is good.there are other things that matter too..