Imo it would be better for you and your wife to eat a healthy diet. Get rid of the junk - processed foods, unhealthy fats and sugar as much as you can. Concentrate on fresh fruits and vegetables, lean meats, whole grains and low fat or fat free dairy. Eat healthy fats like those found in nuts, olives and avocados. Eat a rainbow of fruits and vegetables.
Angel will you stop obsessing over this! How many people will it take to convince you that you're NOT pregnant? You've had four negative pregnancy tests. Your self-induced stress is most likely causing your period to be late.
Since you don't seem to trust what at least half a dozen people have told you on two different boards please make an appointment with your doctor and go to that appointment! We cannot make your period start.