Prepare yourself mentally and spiritually for future loss. It will occur.
You’ll still be deeply disappointed and hurt when it occurs, but you won’t be devastated.
Every positive thing in your life should be treated as a bonus. You didn’t give yourself life and you won’t be able to prevent your eventual death. All the good you experience in between is a bonus.
It’s cliche, but it’s true, things can always get worse. They really can. You must prepare yourself for that. You prepare yourself by finding the smallest things to be thankful for.