You can't, best to get a few condoms.
Birth control doesn't affect the sperm's life span. They can live about five days.
It depends on what birth control method you're referring to. If using hormonal birth control this stops fertile cervical mucus being produced, thus the sperm will not survive for long within the acidic environment of the vagina - a few hours to a few days at most. Obviously if you were using spermicide the sperm wouldn't survive more than around 30 minutes to an hour.
why sperm falling
One exercise you can do is while you are urinating stop and hold it for at least three seconds do it 4 times and work yourself up eventually you will have control of your muscles. this is sort of like a kegel exericise.
Birth control foam does it all the time. If you're asking if the woman can provide an "inhospitable" environment to the husband's sperm, yes.
if a guy does not release sperm for long periods of time the sperm will natrually come out of the body by its self there for sperm is constantly renewing wether it is at its maximum compacity or not
The face that sperm cannot live long, and only one sperm can fertilize egg at one time.
You cannot control sperm
How long does male sperm live
Here it is four years quite a long time, as long as your tubes are okay. Here your partner may have low sperm count.
no, they usually enjoy the extra time ;)