>>1670200The characters live in a multiverse which has an infinite number of variants. In one universe, there is a Spider Woman who through exposure to radiation got sick and was healed by spider blood by her father.
In another, the characters are cartoonish, hench the Spider Pig origin.
Marvel (and DC) use the multiverse as a way to reboot the Spiderman story from time to time. IE: They go to a different universe and start the story over there. This keeps the character at a set age which resonates with younger fans.
So now you know why there are lots of variants of Spiderman! Aren't you a lucky fellow?
O frabjous day! Callooh! Callay!