Thank you for asking about this and giving us an opportunity to respond. My advice is simple:
A year or two of this will create more tension than a home of your own is worth. See this as an experiment that didn’t work out. Get your own place now and stop trying to make something work — and to be blunt, I don’t think this is an opportunity for an extended family therapy intervention. I could certainly be wrong about this, but my sense from what you’ve said is that your parents and your wife need to be separated. The better investment would be for couples therapy.
One of the presentations by Dr. Dan Gilbert at the APA convention this month in San Diego included a piece of research that parents are most unhappy when their children move back into the home. Chances are your parents are not happy about the arrangement, and I would strongly suggest you bite the bullet and get out while the relationships are still repairable.
On the other hand there may be more government help for you to purchase a home than you realize. Here is a link to the government site for housing and urban development with some information that might make your dream a reality sooner rather than later. If it can’t happen now, renting is the best choice for your mental health.
You may also want to have a session or two with a couples counselor as you go through the transition. You’ll want this experience to add to your relationship, not deteriorate it. You may find a referral in your area by clicking on the find help tab above.
Wishing you patience and peace,