Being Military GF vs Wife

I need some advice from you lovely ladies. I am in a serious relationship with a wonderful man. He served three years in the Army and is now National Guard. We are TTC currently. He would marry me tomorrow if I said yes. I will definitely marry him one day but it would be my second marriage and my first one was abusive so I have been giving myself time to heal I suppose. What are the biggest differences in being just his gf vs his wife?