Okay I'll try to give this a whirl.

I have had a b/f for 20 or so years, and we have been in my own opinion living as a D/s couple, minus the kinky sex.

I have always been into bondage and rough sex, but could never find anyone who would try it with me. When I met my b/f I had assumed that I was just an abnormal girl with abnormal thoughts. Kinky sex was just something that was a fantasy.

As for the D/s part, we weren't aware of it, but I ended up staying with him due to the simple fact that he had that way with me, and I was happy doing anything and everything for him. We natuarally clicked.

Eventually as life happens, we started to click apart a little at a time.
Something was definately missing in my life and I found it while using the internet. I found out that I was normal and I had a better understanding about our relationship.

I have discussed things with him and explained myself, trying to make him understand how I feel and what I want. He has made it clear to me that he does not nor will he ever have an interest in what I like.
He at first thought I was maybe going through a phase, he knows now that I am not. As of now we are both at an impasse.

I have never tried to change him, nor will I. It is not possible. He has no interest in BDSM activities, and even if he tried, I know that he would only be doing it to appease me. We would both be uncomfortable in that regard.
As to the D/s relationship, that is slowly coming back a little at a time, but it will never be the same as it used to. As long as I don't label our relationship, I can still have some degree of D/s to it. However the kinky sex will never happen.

So you can maybe change a vanilla person who does like a bit of kinky sex and enjoys submitting or dominating, but I don't think it is possible in a person, who has no interest in changing into what they think is not normal in the first place.