It's not healthy to be in each other's pockets the whole time. If he's away for a few weeks, days, or hours, it doesn't mean he's deserting you and it doesn't have to be traumatic!
Everyone needs their freedom, so respect his and savor yours! Enjoy spending quality time on your own or with your friends.
Learn to live for yourself and don't do EVERYTHING together: you don't control each other, so don't waste your time trying to. Being independent will help you cope with times you have to spend apart, and at worst, if you ever do break up, it will help you cope with the split more easily.