There is nothing like excess masturbation. As you cannot eat more than your appetite you can not do sex or masturbation more than your sex drive or libido. Sex drive fluctuate with many factors most important is you
testosterone level in your blood. Semen is mix of fluid derived from three different source, prostate, seminal vesicle, and testis. Testis keep on producing sperm at constant rate irrespective of masturbation frequency. However, repeated discharge transiently decrease volume and viscosity of fluid derived from prostate and seminal vesicle. It has nothing to do with body weakness. Guilt which we developed due to poor knowledge and misinformation created by quacks lead to depression and perceived self image of loss of weight and disability. Please come out of this. Enjoy sex or masturbation. At same time maintain health balance food.