You know it's bad when you have to take drugs in order to sleep next to your husband. My husband can sometimes rattle the house with his snoring, but it doesn't bother me because I love having him next to me. When he's not rattling the house, the sound of his snoring puts me to sleep.
I don't blame you for being angry about the sex while on Ambien. That's not making love - it's date rape.
As far as I'm concerned your marriage isn't binding under the eyes of God - it's just a legal contract. You married each other because you got caught doing something you feel you should not have done. Marriage is supposed to be sacred - it shouldn't be a punishment. If you're worried about how God feels about this, maybe three years time served is good enough for Him.
I hope you'll be able to find your voice and start singing again.