Try having sex with them on. The secret is not to keep staring at your shoes instead of at the woman, but with a little practice you can learn how to sneek a peak when she is distracted. Position mirrors around the bed room which you can discretly look at while in the act, several so she thinks you are just looking about. Ask her if she thinks that being blindfolded would be exciting for her. Point out that viagra costs about $15/shot, but that wearing the shoes seems to do the trick, plus you can justify buying additional pairs. Point out to her that you'd like more variety in your sex life, and go out and purchase a few different styles, she deserves it. Put them on your feet only after climbing into bed, and remove them if for any reason you need to leave the bed. You can get years of enjoyment out of a pair and they will still have that new look about them.