To all parties - (sorry if that sounds less than heart-felt, because this might possibly the most important subject on the site IMHO) (and a small tribute to "Mashie").
There is a book called "The Four Agreements" which I highly recommend to anyone who can read, at any age.
One of the things it talks about is the futility of trying to change someone else. I bring this up because I think anyone's partner who resists the idea of play of any kind is going to remain resistive.
Conversely, if the partner is just a little bit open-minded, there is very little which will prevent a loving, caring person from at least indulging their partner to some degree.
I, for one, suggest that if we take the subject to our partners as a sexual enterprise as opposed to a kinky one, moving gradually toward our "goal", they might be more open to it. I mean, marriage or a committed relationship is expected to have a sexual component and therefore requires little or no negotiation. Kink is, well, kink; and if not negotiated as part of the relationship at the outset of course requires massive changes in viewpoint.
To follow Mashie's extremely brave example is the best way to live as far as I can see. She just recognized what she wanted and setting about ways of achieving it...so simple, so elegant, and so obvious how happy she now is as a result.
The martial arts term "sensei" actually means "one who has gone before" - so, Mashie, if I have anything to say about it, you are now officially an EC (and wider "life") Sensei: quite literally an example for us all.
I hope this isn't too simplistic, but it has helped me; and hey, it's just like the rest of life - one step at a time...