As for the original Q, you have to look at a lot of things.
Sure, you may be deployed for 3-9mon overseas in a country like Afghanistan. That may not sit well with the fiancee. Logically, you may wanna choose a trade that rarely goes 'in harms way on the frontlines'. Maybe you choose a job that puts you around the country/globe (in relative safety) for a week quite consistanely. That may have a more grievous effect on niner-domestic than having a few month tour every few years.
I am one of those guys who took the trade that's deployed a lot. I went over telling everyone 'nothing'll happen' but sure enough, it did. Mr Big ol'bomb got me and quite nearly killed. When I was recovering, suddenly every relative and their dog had an opinion about me staying in the military. Much to their dismay, I stayed in and 6yrs later, they can respect me for making up my mind on my own. I can look at them and not worry about 'what ifs' and other possibilities.
What I am saying is: Choose a job that you want to do. Choose something that you can see yourself happily in 5yrs down the road and still enjoy it. Over the years, a lot of people on the boards have said 'The military is not a job - it's a way of life' and they are very true. If you are looking for a rock to hold onto during this economic storm of our times, try politics. I read they make good money.