Melissa

Since I don't have a 7 year old with ADHD, I don't feel I truly know what you're going through, but here are some things that come to mind.
Your son is afraid of the dark. Would he sleep in his own bed if there were a light? If so, could you very slowly over several weeks, dim the light as he feels more comfortable? I only suggest dimming the light because I've read that it's hard to get deep sleep when there is light in the room.

Also, I know families who do the family-bed thing, which I think is a personal choice that works for many. So I am wondering if this is a question of you feeling it's inappropriate for him to sleep with you or if you just really need some space, which I think we can all understand.

After my youngest was born and we were dealing with a whole host of sleeping issues, including mine, my husband and I ended up each sleeping in separate beds, one with each kid. I know to some people this sounds horrible, but at the time it made perfect sense. When we needed some alone time for just the two of us, we met in another room when the kids were asleep.

Now my two girls share a bed and I think being near each other helps them sleep.

Good luck!