my grandmother raised me and my sibling since we were both born. She took care of us all throughout our childhood and so my sibling and I both had an incredible relationship with her; she was my favorite person in the world until she recently passed away.
Right around the time she passed my wife and I gave birth to our first child. Not to get too cheesy, but the whole 'circle of life' metaphor really sunk in as I said goodbye to my former "favorite person in the world" in my grandmother and I now get to watch my current "favorite person" grow up. What keeps me going is that I want to have the relationship with my child and ultimately become a grandparent to my child's children in the way that my grandmother was to me. Essentially, I want to continue to build relationships with my offspring, and that's what keeps me going.