Look anon, I start IOT (RAF) in November, I cancelled my wedding because I couldn't see how we would make the relationship work, although my circumstances were vastly different to yours. If you need someone to talk it out with, I'll listen, but at the end of the day these big life decisions are yours to make.
Oh and just to clarify to everyone else:
-the military is more then just the army
-not everyone in the military is a solider
-it's not all about killing people; although yes we are trained to do so other skills do come into play - a quote feels appropriate here "We sleep soundly in our beds because rough men stand ready in the night to visit violence on those who would do us harm." - the men and women of the military are doing an amazing job, the general public are completely unaware of most of it, but trust me if they suddenly vanished you would know about it
-not every person in the military feels the need to jump into bed with people other then their partner, I know plenty of military people in commited, loving FAITHFUL relationships, there are unfaithful relationships in the military, same as any walk of life; unlike in civillian life the military have reprocussions for such actions
-it does take a special person to be a military 'wife' (or 'husband')