why do the ones I love always go?

He came into my life, frightened and shell shocked. Something inexplicible drew me to him, perhaps the frozen, tentative look in his eyes. I walked him for awhile when he was at the shelter, but he really wasn't doing too well there. It was winter and cold, and the places we walked were icy and I'd slip and slide and barely catch myself. In the spring, when the quiet of winter began to give way, I asked if I could take him home and foster him. The policies had changed regarding fostering but a special exception was made. You see, the large blackish dogs don't usually get adopted very quickly as they are so seemingly common. He came home with me, and with a few frightening exceptions, fell easily into the comfort and routine of our home. He'd sleep under the porch and in various spots, like up against the outside wall of my art studio when the window was open so he could see and hear me, making a dugout little nest for himself. I put a dog bed on the floor next to my bed and he'd sleep there tucked into the corner, in a spot easy for me to pet him if either of us got upset in the middle of the night. Our little gentle routines went on for months. walking, patrolling the property, riding in the car, walking in town. Then one day, 6 months after I brought him home. Six months after figuring out he would be the one, the second one who would fit into our family and stay with us, each protecting the other. I was standing on the corner of the street talking to a friend who was tending her plot in our community garden. I saw a handsome couple looking at us from across the street, my friend and I talked some more, but the couple kept looking in our direction and eventually walked over towards us. My dogs greeted them and then the man said to me" Is that your dog?" " and I says " I got him from the humane society" trying to be coy, and he says"that's my dog, I lost him 7 months ago" and he called out the dogs real name, and with that the dog jumped into his arms and started licking his face all over, the man petting him, moved almost to tears by the event. I could tell he really loved the dog and the dog who had initially been afraid of men sure wasn't afraid of him. I grudgingly exchanged phone numbers with him and told him to contact the shelter as I was still officially fostering him. He called right away,but his circumstances had changed from when he lost the dog and his family was now in an apartment that didn't take pets so he wondered if I could continue to keep him until he could make arrangements which I agreed to as I was attached to him and not ready to give him up. I'd done this a hundred times before, helped a dog along, enjoyed them in the moment, and then was happy to see them go to good homes, but this one was diferent. He touched something in me, but as soon as he saw his former family and the 2 young boys he had known from puppyhood, his allegiances switched. He always seemed a little sad and lonely during the time I had him, like he was pining for someone. I'd take him around town for walks and we'd run into the wife and kids and we'd stop and visit and he'd want to jump in the car with them and look at me like" why are you holding me back from my happiness?" The first time the 5 year old saw the dog his heart was torn. After our visit,his mom said "go say goodbye to the dog" and his little 5 year old self couldn't comprehend the whole situation so he crossed his arms and got sad and pouty and refused to hug the dog, feeling maybe like" he left us a long time ago and broke our hearts and now he's back, but going away again with a stranger, and you want me to hug him and get attached again?" I looked at the parents and said"this isn't easy for any of us, including the dog" We saw them a few more times after that, more confusion, and then after about a month they came and got the dog. The whole situation was so bittersweet for me. They loved the dog, I loved the dog. The dog loved them and wanted to go back to them. So once again as had happened 10 years ago when I first started volunteering, I was heartbroken, left in the lurch, caught up in a complicated situation I really didn't seem to have any control over