The only valve to normally have 2 leaflets is the Mitral valve. The tricuspid, pulmonary and aortic valves should have 3. I am assuming you are referring to your Aortic valve having 2 leaflets instead of 3???
Stenosis is one problem associated with the valve, there are others, but stenosis is certainly the most common. Your best solution is to follow the regimes set for coronary artery disease patients. Keeping blood pressure normal, eating healthy foods (low saturated fats), regular exercise will all aim at keeping your valve in good shape. Have blood tests to see how your cholesterol levels are doing. Scans at regular intervals (echo) are also wise as a professional heart management regime because you don't want until you have serious problems. You could develop stenosis and heart failure before any symptoms are noticed and you don't want it to get that far. If you have no stenosis, and no or little regurgitation, then you have no restrictions with exercise. I really hope you stay in the 30% bracket, and if you take the necessary measures, there is certainly no reason why you won't. I know it's easier said than done, but don't worry about it. Stress will cause long term damage and as much stress in daily life should be avoided as possible. This is something we should all do anyway.
I hope this helps