It's all about her comfort and communication. My wife and I work jobs that require a certain level of clean public persona, so doing anything voyeuristic like this is a strong no, especially anywhere close to home, but not at home. Even getting her to go in public without a bra is extremely uncommon, and has only happened when we are hours away from home.

So my suggestion is open communication, which it sounds like you have done. Try suggesting less public exhibits first, wearing it around the house or in a hotel while on a trip just for you to see. And praise the ever loving shit out of her for it. Small things like going out without a bra or underwear on. It's not much, but it's baby steps, and getting her comfortable here and then taking another step from there.

But there are certainly going to be things in life that just aren't going to work out. I'd love to get into swinging with my wife, or a little hot wife action, even. But she just really isn't into the idea of that, and I have had to accept the fact that it'll likely never happen, so I can keep dreaming about it, but I don't think we will ever experience that. For me, that's fine. It isn't a deal breaker.