Nothing's written in stone, as we keep reading right here on this forum.
I could be wrong, but with the way the rules are now, you no longer need to be married to keep your ILR, and if you are out of the country for the 2 years, then you do lose ILR. It may be changing next year, along with lots of other rules about how to become a citizen.
But, with all that said, I agree with the other two, I'd get the citizenship taken care of because then you can come and go between countries as you please (at least under current rules, one would assume they're not going to change that!!)