My husband and I got 'initiated' by getting up enough courage to try out one of our local sex clubs. To make me feel comfortable, we agreed to only to play with each other, but we could socialize with everyone else, explore the venue, watch others making out, and eventually look for a spot where we could do what everyone else was doing. I had no idea we'd generate such an audience. Something about the whole experience had me wanting sex like I'd just discovered the greatest thing on earth. We fucked like newlyweds and I came like never before. I think your wife would be more willing if you just go together, tell her you don't have to do anything, and that you would just play together only. Eventually, after planting the seed, it will germinate and open her up. Be patient. The more pressure you put on her, the more it will make her not want to do it. Good luck!
Since my husband and I first opened up our marriage, I've been exploring my sexuality in ways that I'd never imagined possible. It's truly the greatest gift I've ever received and your wife has no idea about what kinds of amazing experiences that she's missing. Our time is short on this earth, too short to allow religion, government, or society to control our bodies and prevent us from realizing our full sexual potential.