DON'T. Ever. Just don't. Dominance theory has been discounted and encouraging it is strictly prohibited on this and most other dog-related reddits. When people talk about asserting dominance they will tell you to look the dog in the eye, move towards or over it to intimidate it, block it from doing things with your body, using physical means to force it to do things like pushing it off the couch, pushing it when it jumps on you, picking the dog up, hitting it, things like this. These are all signs of aggression to dogs!! Instead of teaching the dog to respect you and listen to you you teach it to fear you. If your husband gives a command and the dog looks away, yawns, or licks his lips he is telling your husband to calm down because he thinks your husband is acting aggressively. You didn't mention how old your dog is but this behavior is very common/to be expected in dogs of an adolescent age (5-12 months, ish). If he isn't responding to commands it's because he either doesn't understand what the command means

is in too high distraction of an area for his level of training

is being commanded by someone he doesn't trust

or he isn't being motivated properly. What kinds of treats do you use?

I'd suggest you look into Kikopup on Youtube, positive reinforcement training, dog body language, etc. Avoid Ceasar Millan, avoid any punishment based training, avoid ANYTHING to do with dominance, avoid anything physical with your dog (always set your dog up for success then reward the success. If he fails it's because you failed to set him up), avoid punishments and adversives (these teach the dog to fear either you because you deliver the punishment or fear that situation. Either way you don't want your dog to be fearful! when dogs are scared they often act aggressively), and teach your husband how to properly interact with your dog. If he's always in a tissy about trying to "assert his dominance" it's no wonder the dog doesn't listen; he's probably throwing all sorts of aggressive signals.