anyone else wonder how sperm can stay inside 5 days

So anyone else wonder how sperm can stay inside a woman and wait for the egg before ovulation? I mean last night my husband and I had sex and after I just laid in bed and relaxed watched tv and fell asleep. I did still feel a little come out and ESP after peeing. Anyone else wonder after peeing and working out and everything else how the hell gravity doesn't win? Anyone ever ask their doctor? I'm so confused how this could even work. Lol