from my recent experience all i can advise you is to make sure that you are in a truly loving and secure relationship, if you are having any minor issues this is going to come back and haunt you big time. I was having some minor issues with my wife, i decided to bring it out 6 months ago slowly, she is to say the least kinky so i figured we could both have some fun, BIG MISTAKE on my part. I now wish id kept my little once weekly / monthly fetish to myself, now she uses the subject on every oppertunity to bring me down and threatens me with it when things are rough. I know there are lots of people here that have had great success and every relationship is different, but id make sure you bring it on slow and try to get her to suggest it, try to manipulate the conversations around and make suggestions, blurting it out my have the opposite of the desired effect.
good luck on which ever route you chooose.