Haha - I always do samples first and then order full bottles of what I like, but Mara says that is what most guys do.
As for guys and scents - I have two thoughts. First, most guys are creatures of habit. He is used to you smelling a certain way based on perfume, body lotion, whatever. And when women start making changes guys wonder what is up and how that change is going to affect them - especially in the negative sense. As in she is changing perfumes because maybe she is thinking about changing boyfriends.
Second, if he is used to commercial scents and their chemical smell, it could take a while for his nose to adjust. Plus he may not really like certain types of scents - foodies scents, floral scents, whatever. I certainly have my preferances.
Just a couple thoughts for what they are worth.