I wouldn't necessarily view it as a defeat. Having 90% blockages in the distal circulation may not be of great significance in your case especially if your heart function is normal. Since you are having exertional symptoms only I would recommend increasing the beta blockers and if the symptoms persist at that point consider revascularization. Since your cardiologist doens't feel comfortable with attempting the revascularization procedure I would consider getting a second opinion.
Just to add. Stress echo revealed 70% LVEF, no problems with RCA or Circumflex and during stress I suffered throat discomfort, jaw ache, shortness of breath, chest pains and nausea. Those symptoms ONLY occur during exertion and never at rest.