I did give the ultimatum 7 years ago, we were separated and when I could see no change would happen, filed for divorce. We did do MC and "dated" while the divorce was pending. She somehow turned her "sex machine" and that is what reconciled things for us. The only thing missing was the SSM point of view, her understanding how no sex hurts me. We fixed some of our communication difficulties got the sex back on track.
Fast forward to now and we just slipped back to where we were before divorce except we communicate now. Do I have to sit down and have the SSM talk again? I did that once already. I did ask her to please read this SSM book. Should I start reading to her as a bedtime story?
As far as the "final" ultimatum I have been waiting to show her how much work I'm willing to put into this. Like Baggy says, show 3 months of solid work then tell her, "I won't live like this any longer and I need you to work on this with me, we have a year. If I don't so any real change by then, I'm leaving."