SEALs ha, not an easy path there m8, physically and mentally it'll take a lot out of ya, and will replace it with even more. Just remember one thing, once you started something finish it. As for getting married, I didn't, but i can tell ya one thing its sure feels nice to get that letter, to know that someone is waiting there for you, that where ever you are you are not alone, and most importantly you have somewhere to come back. And you will want somebody to comeback to. My commander, while on leave walked a girl home because it was dark, and she lived in the bad part of town, he didn't know her, but he asked if he could write to her, because he had nobody else, but us. A lot of guys who came back, turned to alcohol, drugs and such, you see shit, shit that shouldn't be happening in todays world, and it eats at you slowly. You can be all macho and tough, you don't even need to whine, or tell anybody about what happened, but you need somebody to say "I'm here for you." That will ease you life after greatly. It doesn't need to be a girl it could be a friend who cares. But this is a double edged sword, if god forbid something were to happen to you, that will hurt the ones who care for you a lot.
Best advise I can give you here is think it through, and once you made up your mind don't look back.