Toy, I hope the opinions aired on this thread haven't driven you away. I wasn't going to return to the discussion at all - I have found it upsetting and everything has been said, again and again.
But I've been thinking about you all day, and wondering about your perspective on this. I'm currently going through the adoption process, and one of the things the social workers insist you read up on and understand is the impact of disruptive/distressing early years on children.
I expect it feels to you like we are all saying 'poor little boy' with no understanding of how difficult he is, day in day out. It's probably very hard to see him as a sad little boy. But that is what distressed children are like: angry, disruptive, often difficult to love.
You say you've tried everything, but you haven't tried keeping trying. Honestly, it takes years of calm, consistent parenting - not months - to start turning round a damaged child.
It sounds as though you are waiting for your stepson to realise the error of his ways, and change them, before you will be willing to do the same. But that won't happen, will it? 10-year-olds don't have that level of self-awareness and thoughtfulness, and damaged 10-year-olds certainly don't. It may seem unfair to you that you should be asked to change first, but it is really and truly the only way forward. There is no alternative, short of giving up on this family altogether.
If you want to hold this family together, you should do two things. First is to apologise to your stepson for telling him you hate him. No buts, or self-justification, or asking him to apologise too, just saying sorry, it was a terrible thing to say, you were angry and it came out all wrong, you'd really like to make things better. You never know, he may reflect on times when he's been angry and done hurtful things and then regretted it, but don't ask that of him.
Secondly, get professional help. You can't not - this problem sounds too big for you to handle without. Many posters here have made excellent suggestions of who to turn to.
I really do wish you luck. You've been to hell and back yourself and I'm impressed by how you managed to pull yourself out of a very bad situation. See this as another bad situation that you have the intelligence and courage and persistence to turn around. I'm sure you and diva can do it, you just have to accept that the responsibility lies in your hands, not those of your stepson.