I am never satisfied with anything please help?

I am a 45 yr old male and have a 17 year old son , just like most people my age I have my share of heartaches such as relationship breakups , death of a spouse and death of my parents. In every relationship I have had I was always told that nothing ever makes me happy even now I have a wonderful fiancee you loves me with all of her heart, he kids accept me , we own a beautiful home together, I have a car that I always wanted, and a good stable job but no of that truly makes me happy and this has always been the case I reach a milestone with something but instead of basking in my accomplishment I want the next thins , nothing is ever good enough . I have sought conseling for this and still to this day still continues . It seems that I am wasting my life , I am healthy and so are the people around me I see no problems and I love the person I am with but find fault with everything in my life . Has anyone else had this problem , please help I hate living this way