This is a topic very dear to me - I came out to my husband after 5 years of marriage (and a year+ of dating). I felt an enormous amount of guilt for hiding it for so long, but I never knew how to tell him. This website actually helped me find the courage. Luckily for me he was open to it, and while he doesn't fully understand it, he KNOWS its not any form of pedophelia, and he is willing to try to understand what it is and what it means to me.
To give him a better understanding of the fetish/lifestyle, I've been researching it and picking out well written articles on AB/DLs for him to read. I am well aware of how very lucky I am that he is willing to explore the fetish with me. For me the confusion lies in how to incorporate this fetish in to our sex life, so I've been suggesting to him that we reverse the roles, and that he plays the baby and I play the mommy, so that he can see what it feels like, and maybe he'll come to like it to (hope this isn't TMI, but so far so good!). He's open to it and we've laid out boundaries and we both know that if EITHER of us feels uncomfortable in any way, we'll pull the plug on it.
If your wife loves you for who you are, then ask her to understand your feelings and what this fetish/lifestyle means to you. If she loves you entirely (as she should because she is your wife and she knew this going in to the marriage) then she should make an effort to learn more about AB/DLs. There are several good threads on this website that have helped me get through to my husband. Like I said, he doesn't fully understand it, but he accepts it, and he loves me.
Sorry, this is probably a really repetitive response and if I offended anyone I apologize (I'm on painkillers for my back) but coming out to your spouse and being accepted by them is incredibly important.