Wow, I've had totally the opposite experience--my bf took over all the shopping this last year (we used to do it together) and it's been fine. Took a few tries to get the hang of things, but it's been no problem since then. It's funny, too, since I was really reluctant to give up control of food shopping, but now I'm glad I don't have to drag to the store all the time.
Also, I grew up with my dad always doing all the grocery shopping. He's 86 now, so we're talking the 1950s when he started doing the shopping for my mom. He's a real pro at it, too--picks out the best fruits and veggies, and used to change his drive home from work every day to go to different stores that had lower prices on certain items.