I don't know, I was leaning toward she would rather have you spend money on the kids than her, and then found out she knew you took a picture of her behind in her yoga pants. Now, I wonder if coupled with buying something as intimate as undergarments, she is feeling a little creeped out or objectified by it all.
I guess 30 years of marriage have taught me that if you think you upset your spouse, talk about it.
I plan on it, it just hit at a bad time because now I can't talk to her until at least midnight, maybe tomorrow or the weekend. She was fine with the pic, that was months ago. She's also not creeped out by me buying her skivvies, for pete's sake, we are married. Heck, most of the time with the VS coupons, she has me go get them on my way to work, it's a lot more convenient for me to than her, I just know what she'll want.