If you've been DM'ing for two years with no chance to play, SOMEBODY in that group knows the rules well enough to take a turn DM'ing! Get the loafers off their duffs and tell them to get cracking! They ain't gettin' any more free rides off of you!
Seriously, there may be a player in your group who has an expressed or hidden desire to try their hand at the DM screen, especially if you enjoy your job and make it seem like fun. Sometimes a little coaching is all that's needed. If you find a volunteer, give them as much help as they need, coach them a little, if they ask for pointers feel free to give them, but don't offer until they ask - just let them know that you're glad to offer opinions or guidance.
I have a casual player who was actually very good at tactics in battles - but he was a first time DM, and got turned off at the feeling that he was a novice. The important thing is to never let a first time DM feel useless or poor at the task - because everybody started with a DM guide and a campaign idea at one point.
Fortunately, I have one other person in my group who is a ready DM, and we trade jobs quite frequently, so I do get a chance to play. But sometimes, when you can't find 'em, you just gotta take a seed and grow one.
