No scientific explanation or psychological rationalization can take away death's sting. Little can.
From my own experience, my faith has been a great source of strength and comfort in the face of the losses I've endured. In the here and now, I keep my loved ones alive within my heart for as long as I remember them. I continue to love them in my act of remembering and carrying on their legacy; and loving one another is the single most important aspect of my faith. Of course their abscence brings me pain, but I find great joy when I think about that day when I will once again see my loved ones who have passed into the realm of all that is unseen.
Our beliefs give us great comfort in times of loss and difficulty--the knowledge of life after we leave this world gives us hope when all else feels utterly hopeless.
"...while they were thus drawing towards the gate, behold a company of the heavenly host came out to meet them: to whom it was said by the other two shining ones, These are the men that have loved our Lord when they were in the world, and that have left all for his holy name; and he hath sent us to fetch them, and we have brought them thus far on their desired journey, that they may go in and look their Redeemer in the face with joy.
"...Now I saw in my dream, that these two men went in at the gate; and lo, as they entered, they were transfigured; and they had raiment put on that shone like gold. There were also that met them with harps and crowns, and gave them to them; the harps to praise withal, and the crowns in token of honor. Then I heard in my dream, that all the bells in the city rang again for joy, and that it was said unto them, “enter ye into the joy of your Lord."
from The Pilgrim's Progress)