Hi Michelle,
As a stray your dog may have been given a good reason to mistrust certain people. If your husband is trying to approach her to give affection then try having him only call your dog to him to do so. Allowing her to feel like she has a choice, and that her personal space won’t be invaded, can make a big difference for some dogs. If he is just walking around the house though, and she starts barking at him, calmly put her out of the room until she is quiet and then allow her to return. We want to show her that barking at your husband means she will be removed…there’s no need to tell her off or say anything, just calmly remove her.
There is likely a few other things contributing to her behaviour so maybe take a quick look at my website TheOnlineDogTrainer.com where you’ll get a better understanding of what’s going on and how to overcome it…it’s a $1USD trial for 3 days…all the best Doggy Dan