How long does it lift for a sperm to die?

i had sex beside my bf on sunday and just yesterday, and very soon im scared make happen i saw light spots on my underwear. My finishing menstrual period be on december 19th, and it takes me 5-6 days to obtain over it. So that means my subsequent period should be around the 25th of january. So yeah, thats why i be asking cause im exceedingly far to having my time and i heard that it take sperm to die within 3 days, right? ASSUMING you've get a standard 28 day cycle, your subsequent period should arrive on the 15th. If you're expecting it on the 25th, this process you have a 38 daylight cycle. Are you counting it right? You start counting your cycle as your first period year being light of day 1; the LENGTH of your bleed-cycle (i.e., period) has NO deportment on your cycle length.
As for your question, the AVERAGE length of time surrounded by OPTIMAL conditions allows sperm to live APPROXIMATELY 72 hours. Things can effect this, such as a high bitter level contained by the vagina (high acid kill sperm faster), as well have HIS diet.
If you're concerned with pregnancy than you hold an obligation to use better contraception than simply crossing your fingers and hoping for the best. Especially if you're not counting your cycle days properly.
Within 3-5 days sperm can live inside your body.
Best Bet: Birth Control =]
sperm are really unpredictable. but i believe that is right