What is the best advice you have for having a successful relationship/marriage in the Army?

Professional marriage and career counseling - a lot of counseling - to ensure you understand each other, communicate well, argue without destroying each other, preserve spontaneity, empathy, affection, and know when it is appropriate time to go. Warmest Regards, Sandy :)
CPT Jack Durish CMDCM Gene Treants MAJ Joseph Parker

Stay Single as long as possible, but when you marry, keep your priorities in order. My wife knew that my career was important to us both and we were part of the Navy together as a team. If I had to deploy I left her prepared as much as possible. We discussed what to do in case of emergencies with the house, car, etc and had all of the needed paperwork. That was the logistics part.
Then we also covered our marriage as 1LT Sandy Annala talked about - "communicate well, argue without destroying each other, preserve spontaneity, empathy, affection." We are still married after over 40 years, 20 in the Navy.

Be honest and upfront about the requirements the military will place on you with your soon to be spouse. Tell her/him exactly what field time entails, deployments, and the lack of communications technology you will often encounter while out. Go through the budget, budget in wiggle room (your spouse is human and has human needs they don't always account for). Put as many bills on an automatic payment plan as possible. Plan to have at least three bank accounts. Set an allotment to yours and theirs. The rest will go to the main, automatic bill pay account. Every time a reenlistment comes up, talk it over with your spouse and make sure they still want to be your support structure. Just like you can ETS, the spouse might want to return to civilian life as well. Make it a joint decision to continue service.