black widow's widower

i had a strange experience today. as i was picking up straw to mulch the spring garden, i noticed a jet black spider a couple inches from my hands. yikes, i drew back with intuitive fear. i grabbed a stick and came back to the spider, prodding it on to its back. with a couple quick delicate pokes, the creature curled up in a ball, like an animal trying to protect itself by playing dead. i turned it over and, lo and behold, there was the signature red hourglass on its underside. a black widow. a highly venomous spider here in our yard. a beautiful pitch black arachnid. i squatted there several minutes, keeping the spider from crawling away but not hurting it either. what was i to do? move it to a place where no one would get bitten? let it be? kill it? i couldn't decide. and what's more, i was struck by its delicateness, its shyness, its non-aggressive nature. i had grown up as a kid talking about black widows like they were little monsters just waiting to get the chance to BITE! and kill their helpless victim. yet here was a black widow just like any other insect or animal, trying to protect itself from something much larger. i decided that i had to make a decision right then and there. i couldn't go back to the house to fetch a container or think more. there were too many nooks and crannies, too many garden tools lying around that it might hide behind. with sudden decisiveness, i crushed that spider. i took its life in a moment. i still feel guilty and strange about killing it, and that's why i write this now. such an extraordinary little creature, a thousandth our size yet contains poison to render the weak dead and the strong weak. beautiful jet black, but with a bright red hourglass on its belly. rather shy, but kills its mate after copulating. i killed it out of fear, to keep me and julia safe. could something else have been done? should i have killed it? what do you think?