I'm sorry for all that you went through as a child. It sounds like he is a positive influence, minus the minor nuisance of him talking all the time. Have you though about a hobby? Something to distract you when he rattles your nerves? Sometimes we annoy the hell out of spouses and never really get it. My wife has a big pet peeve of me turning on the TV when she is listening to music. She hates conflicting sounds and finds it rude. She told me (or rather gave me the stare) and now I don't do it anymore, or if I want to watch TV I tell her before I turn it on. Can you try talking to him and let it him know he doesn't have to fill the silence? Just my thought.
My wife also proposed to me. It was kinda weird and uncomfortable, but it was genuine. We were dating for about 2 years and we were still in college, around 21 years old I think. We were in her moms house in my wives room, and she was drinking a little. She had a heart to heart moments and laid soul out to bear, basically saying I was the person she wanted to spend the rest of her life with. It was a real genuine moment, minus the jagermister and Cheetos kiss, that was kinda gross. A month later I bought her a ring and proposed to her at the place we first meet. Just thought I would share that.