How long are you deployed in the Navy?

It depends entirely on the ship you're on and the current mission. Surface vessels typically have longer deployment schedules than submarines, because they are more easily resupplied at sea. Submarines only resupply in port.

A typical submarine deployment is anywhere from 3-5 months, but a Carrier Task Force can be deployed from 9 months to a year or more depending on the current mission and if there are any global crisis. However, since they have aircraft, sailors can be rotated if the mission requires it or there's a family emergency. Submariners don't have that opportunity unless they're close to a port and it won't impact the current mission.

Being a sailor is not easy - unlike the other branches, sailors are away from home more than they are at home. I calculated during my first year aboard my boat (I was fast-attack submarine sailor) we were at sea or away from home port a total of almost 300 days. However, once you're at sea, you always want to go home, and once you're home you want to get back to sea. There are advantages to being at sea also - you're away from the everyday BS that goes on in regular life - bills, shopping, commuting, etc.

Every sailor I've ever known always complained about being at sea, but on the other hand wished they were at sea again also. It's hard to explain without experiencing it first hand, but I wouldn't trade the experience for anything. While divorce rates can be high, those that don't make it probably wouldn't have lasted anyway. Typically the spouse isn't prepared for being alone and running a household. I was fortunate in that my wife was a sailor as well - we were enlisted and married during a period where in-service couples were rare and there wasn't much policy. At that time, women couldn't serve on board combat vessels yet either. But being a sailor, my wife had a better understanding of what I was going through and was able to cope better. We just passed 28 years last April.