So is there a cure for it?
yes.
Better ammo!
And that's not just a snarky answer, its a serious one. "Better" meaning better suited to the gun so it doesn't lead the barrel.
All barrels are not the same, all lead bullet ammo is not the same. A specific bullet and load may lead in one gun, and not in another. And, its not the type of rifling or how it is cut.
Leading, or not leading depends on the relationship between 3 main factors,
(plus the barrel itself)
Size of the bullet in relationship to the size of the bore
Construction of the bullet meaning the alloy it is made from and its hardness
and lastly, the velocity of the bullet.
If the bullet is too much over, or under sized for the barrel, it can lead
If it is too soft or too hard it can lead.
If it is driven too fast (and how fast is too fast will be determined by the relationship of the other factors) it can lead.
When you buy factory loaded lead bullet ammo, it is a "one size fits all" thing. It MAY be just right for your gun. It may be ok for your gun, and not for you're wife's gun, as you have seen.
My point here is that one can get (usually you need to make it yourself) lead bullet ammo that is correctly "tuned" to your gun and won't lead. But, you can't count on that just buying ammo with lead bullets.
There are a lot of variables that need to come together just right so there aren't any issues. SOMETIMES factory ammo does that with your gun. Sometimes not. They can all be figured out nd adjusted to a desired result, but that takes time, practice, and a bit of handloading expertise.
If that's not your thing, or you're not willing to go there, then you need to try other brands of ammo & loads until you find one that behaves better in the desired gun.
Get some different ammo for the wife's gun. Shoot it, see if you get different results. Then try a third brand. Once you find one that performs acceptably well, buy a bunch of that and use it until/unless you want to get into cast bullet reloading.
Polishing / lapping a rough bore is always an option, but remember, once done it can't be undone and done badly can ruin the barrel.
You can also just "break it in" by firing a few hundred rounds of jacketed ammo, and then see if you have the same leading problem you did before.
Lots of possible options, but I'd recommend saving work on the gun as the last thing you try. Try some different ammo first. "Polish" the bore with a few hundred rounds of jacketed ammo, then try different brands of lead, and see if anything has changed.
After that, if you still have a leading problem, come back and let us know and we'll talk....