My boyfriend's two testis are missing. how can missing testis will shorten his life every time he have sex please describe me about this siruation?

Shorten Life?: Not a threat to life. Are they really missing? Does he say that they have never been there or has he had a urological procedure? This may or may not have sexual performance issues but would depend on what is going on. If it is an issue have him seen and examined by his doctor.

Not exactly: Missing testes must be searched for. If they are found in the groin or abdomen, they may be moved down to the scrotum so that they can be examined by himself and his doctor for testicular cancer. The "shortening of life" can happen if a testicle gets cancer while sitting undetected in his abdomen... having lots of sex makes no difference from a "missing testicle" perspective.