Hi,
I try not to keep dangerously venomous critters except for a few rear fanged snakes and various spiders, but i do indeed keep widow spiders.
I own and have experience with southern, brow, northern and western widows and they all are generaly very laid back and slow moving and i have never ever had problems with them. They never "attack" or attempt to bite and even when guarding an eggcase they are still generaly calm. hey all eat very well and make great captives and a great display animal.
The widows i aquired last march are still living and doing fine and continue to lay egg cases wich must be taken out to prevent infestation of many many tiny widows, I feed them large crickets wich even though they are sometimes larger than the spider , they take it down quickly and easy, just dont overfeed,
i feed them a large cricket every week or 2 depending on how fat they are.
You must keep them in a small escape proof cage that is secure , preventing it from falling, Substrate is not needed but you can use a substrate like sand that wont keep in moisture build up.
Give them a few twigs or something for them to build a web in at the top of the enclosure.
As for venom,
Widows can be dangerous if you get bit which, as long as you are not dumb should be pretty easy to avoid.
Generaly widows are not usualy deadly but mostly painful.
What Kind of widow do you have?
can you get a pic
and what are you keeping it in?
hope this helps
Kevin