You poor thing! My Husband occasionally forgets to brush before bed- I let it go cause it's not that often. It's usually when he crawls in bed with a vodka tonic-lol.
If I were in that situation, I'd pop little listerine strips in his mouth unexpectedly, start cooking everything with mint, and constantly offer him gum... but I'd be super cute, sweet, and nice about it. I'd make it a joke and we'd laugh. If you're too afraid to start a fight, that's not a good healthy thing in any relationship- imo. Since he treats you so well though, I kinda understand not making a huge deal out of something that isn't a deal-breaker.