Heavy masturbate can cause infertility. is this true?

No: This is one more unfounded scare story in a world that's difficult enough as-is. Long abstinence results in resorption of some of your fluid but not your sperms, so the sperm count goes up; if you ejaculate often, the sperms are diluted by the fluid that makes them work. That's the basis of the claim that it "lowers your sperm count." embrace being an adult.