Does your better half think you are weird for thinking buying an everyday essential used by everybody is embarrassing? Are there any other normal everyday supermarket products that you are too embarrassed to buy?
That's not really being embarrassed so much as not buying a product she doesn't use and/or just being judgmental. Well, unless she ever goes to the shop for you but refuses to buy a beer for you because you fancy one and can't get to the shop. That's just mean.