Just playing devils advocate here...
Maybe the wifey has a valid point, maybe the op is historically a total fukk up and will inevitably leave the safe open or a loaded gun out on a table.
Most likely not but...
One thing to consider is that maybe the wife's concerns are not complete ignorant hoplophobe crazyness. They might just be ignorance, or maybe there's stuff we're not considering.
Is he a flake? Does he have a habit of leaving the safe unlocked? Does he currently leave guns or gun stuff all over the house?
Even the best of us will, eventually, f*** up and forget to lock the safe, or leave ammo somewhere we shouldn't.
Those are legitimate concerns, not fabricated left wing propaganda.
How serious those risks are, and how those compare to the risks of cribs or cleaning products or stairs or electrical outlets is a completely valid topic of discussion.
We all have our built-in biases we get from our parents and friends and the media we consume. It's entirely possible there's some unreasonable fear that can be assuaged with knowledge.
We have to assume the OP is not a moron.
That seems like a reasonable place to start.
But even in the case that he's not a moron and not a flake and doesn't leave stuff around by accident, there's the very real, however small, risk of lead poisoning. Lead is very, very bad for a fetus, infant, young child, etc. Bringing guns and gun stuff into the house increases that risk by more than zero. I don't mean the risk can't be mitigated, it just that it's a real, legitimate concern.
She might be a 10/10 in every other aspect, so a little compromise might be worth it. To be clear, when I say "compromise" I don't mean "give in", I mean "everyone gets something they want, just not 100% of what they want".