My son is grown now, but I totally relate to what has been said. I wasn't dx'd till his mid-teens, and when I told him, he wasn't surprised in the least. He said something along the lines of. "Yeah, I know." See, HE was the first to "dx" me(!) He was 13 and pointed to a med ad (I think it was Abilify) in a magazine which showed this lady in all kinds of moods and said, "that's you". I of course denied it, but truth was, the only grounds on which I could do so was never having called anyone at 2 am(!) The rest? Guilty as charged.
I too never considered a second child. One was overwhelming enough. At one point (teens I believe), he said "You're not like other mothers, that's cool though." Kids are more forgiving than we might think. He is 25 now, and we've always gotten along great. He knows I've got a lot of empathy and won't judge, so he is quite open with me. I hope this gives you hope.
The only bad news really is that I think he got it.