I think what one can gain from all that is said that it can really go either way. When I reported for Indoc for the class of 2013, I was suprised by how many guys had girlfriends back at home. I remember hearing about the first breakup maybe a day in to Indoc. As Indoc went on, a few more kids got dumped, or decided to break up. At the end of Indoc, there were still more break ups. The next big wave of break ups was during Thanksgiving break, when some kids went home for the first time. A few more happened over winter break. After that, things settled out some, until the summer, when B-split went to sea, when a few more guys got dumped. Even more got dumped over this first sea term, but after that, things started to settle out. I think the best advice is to set goals, small goals. The relationships that make it thru first sea year tend to remain pretty strong. However, getting there is the hard part, and even then, nothing is certain.
I was dating a girl for maybe 2.5 months before I went to KP. We made it thru Indoc, first tri, second tri, third tri, my first sea term, my 4th tri and then one month into my second sea term. Getting letters from my parents was great during Indoc, but the letters from my then girl friend were the best. As stated by someone else, write him letters every day, it will mean the world to him. I carried my letters with me in my BDU pants pockets and I read them when I could. I also put alot of effort into my relationship. I secured a leave to go home at the end of Sept, Plebe year. I got to see my parents, and I managed to suprise my girlfriend (whom I had told I wouldnt be coming home until Halloween). My then-gf lives about 6 hours from KP, but I would make the trip to see her, on average, 1.5 times a month. This is on the high side for most relationships. Something to remember, when he does steal away from Kings Point and comes home to see you, dont be suprised if he passes out on the couch at 9:30 on a Friday night. Do not take it personally, waking up at 5:30 in the morning every day and going to bed after 10pm is very taxing.
You can ask everyone about the odds of getting thru KP with your significant other, and you will hear all kinds of different things. The thing to remember is that everyone is different. You can date someone thru all of high school and think you know all there is to know about them, but when they go to Kings Point, I promise you, they will change. You may like this change, you may not. You cannot stop this change, and if you try, you will just cause him to push you away, which is obviously not good. As someone said previously, sit down and have a face to face talk about what you want in your future and what they want. Yes, it is true that some graduates get shoreside jobs (aka they can come home every night), but dont put all of hopes in this basket. Prepare for the worst, hope for the best. Also, what he wants to do after graduation will most likely change 10-15 times before he graduates. He may be Gung-ho Marine Corps for his first year there, then go to sea and be all about sailing for the next 2 years only to wind up doing something completely different. Odds are, your dreams and aspirations will also change, and for your own sake, when it comes to life changing decisions(like choosing if you want study abroad or stay at home so you can see your BF maybe once of twice more), try and think about whats best for you, because at the end of the day, the only certain thing in life, besides death, is that you are who you make youself. (Taxes can be avoided).