Well, I put pressure on my husband to keep fit - I'd like him to live a long and healthy life. So, he goes to the gym for me.

However, I'd probably shoot him if he bought hair mousse, aftershave, etc.

Marketing has a lot to do with it, but women do have influence on the men in their lives. (and the marketing is targeted to make men think that women want them to use those products, so it's not surprising if men fall for that spiel)