It's been said already, and probably better than I could put it, but you need to be prepared for a life of instability regardless of the intent behind NEM to provide more stability.
The RAF is shrinking but our commitments remain as high as ever. What does that mean? Options for posting are becoming increasingly limited which on the plus side means you stand a fighting chance if being able to put down roots in a specific part of the country with a reasonable degree of certainty that you probably won't find yourself suddenly posted to the other end of the country. That's as close to domestic stability as you're likely to get these days.
The flip side to this shrinking force is that those that remain are spending more time either deployed on ops, on exercise - either exercising or 'flying the flag' for UK plc or in support of our allies or in training in preparation for all the above. Under the UN concept of 'responsibility to protect' combined with what in essence is a fairly liberal government means that we are often getting involved in places around the world that won't appear to be immediately obvious - how many people thought they'd ever be going to Nigeria or doing air policing over the Baltic as Russia flexes it's muscles on the other side of the border? That isn't going to change any time soon and you will be spending a lot of time away from home, sometimes in completely unexpected places that need you to dig out the atlas just to find out where they are. And often it's all at short notice - 3 days notice for a Balkans det, 5 days notice to go to Baghdad as a LO attached to the US Army in 2003 and 10 days notice to go to Helmand in 2006. You quickly become used to hearing the loaded questions "you haven't made plans for summer/Christmas have you or you do have insurance for that holiday?"
That's pretty much just the basics of life for anybody on the 'ops' side of the RAF these days, so your ground crew, ops and support staff will all be in the same boat and you as an officer will be expected to set the example to those more junior types who may also be struggling with the demands of operational life.
As you proceed up the ranks, time away on ops will decrease as your seniority increases and those coming in behind you take your place on the front line. However, it doesn't get any easier just because you aren't deployed to some random part of the world and you will more than likely find yourself working the same sort of long hours in a HQ somewhere, whether that be PJHQ, Air Comd, 1/2 Gp or even Army HQ or MOD. Even with NEM hinting at the prospect of stability there are plenty of other factors that work to undermine that concept. It's not going to be a smooth life by any stretch of the imagination, and certainly not compared to your average civilian career, but it's one hell of a ride. And like it or not your significant other will be a part of that whether you intend it or whether she wants it.
I'm not going to say get rid - that was the helpful advice we got on day 1 of IOT - "women are trouble and a distraction you don't need in training" - only you can make that call. The right woman by your side can be an invaluable anchor to reality and a source of support and a shoulder to cry on the days when it all goes wrong. The wrong woman by your side will invariably be the cause of the tears.