The past comments are excellent, and truly worthy of your consideration.
Along with those thoughts, I’d like to add that, because we all have so much, and have done so much in this world, at some point, this life CAN seem empty after you’ve “done it all.”
As you, my wife and I (kids are gone) pretty much have everything we want, and have been just about everywhere we want to go, but, because of our spiritual beliefs, we realize the best is yet to come.
Once you truly and fully realize that, you stop clinging to what you think should make you happy, and realize the deep sense of happiness and peace you seek comes from a relationship with something outside of yourself. For us, that peace and happiness comes from our relationship with God, and from helping our families and others in any way we can.
We all want the best in this world to last forever, but good, bad or indifferent–EVERYTHING IN THIS WORLD IS TEMPORARY–get over it. Once you do, you’re free.