Sometimes the strongest thing you will ever do will be to let go of someone. It will be painful, you will suffer guilt, and you will second-guess yourself, but for your own sanity and quality of life, there will come a time where you hand them to God, with your love, and trust Him to be who and what He is. May our Lord comfort you.
We can't be afraid of change. You may feel very secure in the pond that you are in, but if you never venture out of it, you will never know that there is such a thing as an ocean, a sea. Holding onto something that is good for you now, may be the very reason why you don't have something better.
Sometimes the door closes on a relationship, not because we failed but because something bigger than us says this no longer fits our life. So, lock the door, shed a tear, turn around and look for the new door that's opened. It's a sign that you're no longer that person you were, it's time to change into who you are. It's going to be okay.
You will say good-bye for all the right reasons. You're tired of living in wait for his apocalypse. You have your own fight on your hands, and though it's no bigger or more noble than his, it will require all of your energy.
It's you who has to hold on to earth. You have to tighten your grip - which means letting go of him.