It doesn't really work that way. Jackie's a host for his backer. Where Jackie is, the Darkness can get to, and it won't let him die until he sires a son, at which point Jackie dies at the moment of conception and the Darkness passes to his kid and goes dormant until the kid turns 21. Jackie doesn't want to die, so he doesn't so much make with the sexing anymore. Short of that, he's basically immortal.
Probably won't be that way for me. If I'm here, I'm going to be looking for the fights I need to fight to keep the apocalypse from happening.