God this is getting tedious! But there is never going to be 100% satisfaction.
Mr Jones - you are in a moblie grade - something that was made patently clear when you joined, something that you and everyone else who stayed in the company were obviously happy with at the time and therefore decided to stick around and take the fairly decent pay.
The fact that you have not been moved around and have in fact been fairly static should be considered a bonus. You are now being asked to move. Yes - you have a valid point reference the career of a partner. You will just have to do what everybody else in every other walk of life has to do... weigh up the balances and then make a decision. If that means either you or your partner switching jobs, then that is what you will have to do.
People have been happy to take good pay and conditions for years, without having the hassle of moving every couple of years. Well now, just this one time, you are being made to move. Thats what the 'mobile' part of the contract you agreed to means.
If you do not like it, thats bad luck, put up or shut up! People in NATS have been cosseted for so long they should look and see what happens in the real world. We are getting a pretty good relocation package, a hell of a lot more than someone in the Forces gets, and we get paid a hell of a lot more than people with comparable or greater responsibilities in the Forces.