My wife is the exact same.
Let me guess, you get so excited about a great deal you got, and you HAVE to tell her cause you love her and want her to experience it to, so you start the conversation ff with, "I know you don't care but...."
Yep, I know exactly what you are experiencing.
My wife doesn't just buy me stuff on her own due to the fact she doesnt know what I already have. But what she does do is look thru our "Watch List" on EBAY and tells me on Birthdays, Christmas, Valentine's, Etc... that I can get them.
Also, she just, this last weekend, got her incentive check, and told me I can take $100 and buy what I want. She is in Branson right now, so when she gets back, i will verify AND GO SHOPPING!!!!
You and I are pretty lucky huh!