Yes, there's one word that needs to be cut, not acceptable on this board. Fourth line from the bottom.
Your pain comes through loud and clear. I had the most wonderful stepmom ever. She embraced me and included me in her life on the spot. Many people, not just JW's, can be amazingly selfish, though. For these people, anyone else in their loved-one's life is a threat to their affection. As if love were a loaf of bread that must be sliced up fairly. Too bad if you get the crumbs!
But in my experience, love doesn't work that way. The more I love, the more it expands, like an ever growing bubble that never pops.
Your dad and your stepmom are the losers. They are squirreling their love away like crumbs. The more time you spend with them, the more bitter you will be. I suggest you adopt new parents for yourself, maybe from a local nursing home. I also suggest you spend your time getting to know these new people, their interests and cares, and refrain from talking about your bitterness to them. That way, your own generosity will grow, and you won't drown in your own unhappiness.