NTE, I didn't want to do the ultimatum, either. And I didn't do the 3 months beforehand, unfortunately.
But giving the ultimatum was important. I think it was the only thing that convinced my wife that I was serious. I had never been unclear about exactly what sex meant to me and exactly what I needed in that regard, but she had always blown me off. I became convinced that she had to understand (I'd said it in so many words, and she'd said "OK, that makes sense"--but just because a woman listens to you and says she understands, doesn't mean she understands what a man is saying.) and therefore she must just think it was OK if I suffered. I figured she was out of love.
Your wife knows how desperate you are not to get a divorce. The fact that you are willing to do it anyway might shock her into thinking about what would drive you to choose such a thing.
