GKC,
I racked the slide of my new Kahr K9 a couple hundred times before taking it to the range. No malfunctions during the break-in period or the approx. 100 rounds since (only had the gun about 6 weeks and to the range twice).
That being said, if you like the LC9 why not stick with it? As you say, you and your wife can share mags, or if she's not carrying (like my wife sometimes doesn't) and you have the LC9 as a backup pistol, you have a gun she is familiar with to arm with her if needed. For a pocket gun, I would definitely prefer having the manual safety on the LC9, and from what I can see the magazines for the LC9 go for less than those of the Kahr.
Just some things to think about, YMMV.

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