Dont worry!
Worry only if you find a mens undergarments other than your in the drawer. A toy can never match the human emotions you bring. You should be happy she is loyal to you. If this bothers you that much you should talk to her about ways that you could help her climax regularly so that you don't have to feel like your competing!
By the way, I was in a sex shop in front of Moulin Rouge the other day... I didnt know that those "devices" where THAT expensive... some pretty exotic too!
My girlfriend and I often enjoy using these toys!! On eachother or watching the other one using it.... believe me they are fun and very satisfying!!!! ;-) All it takes is an open mind and imagination....!!!