Would a single testicle affects the sexual life and satisfaction of my wife during intercourse. also is there any way to measure my sexual power?

Good news: You're a man, and i'll bet you can name dozens of machines that have "built-in redundancy", parts that take over if another part fails so the machine will work just as well. That's your spare testis. The only "measure" is what your wife says. Being a great lover involves much more than just your erection & ejaculation; keep asking her what she likes best involving every part of both bodies.