It sounds like when your husband leaves through the 'wrong' door, it makes your pup anxious. Dogs like stability and normal. I'd have your husband and you walk your pup through this door several times a day till it realizes that going through any exits in your home doesn't mean anything to you...so it shouldn't mean anything to your pup.
IMO - here's why. To your dog, your front door means something to be worried about. If you guests come through that door, your dog is going to always associate your guests as being an event to be worried about. You want to show your dog that guests are a non-event, therefore the door is a non event. Using your husband as a training tool is a great advantage!
Side note - sometimes 'huffing' like that means the dog is trying to take in as much air scent as he can. Or it could be small half barks. Watch him next time and see if he's trying to take in scent or trying to vocalize. Kinda interesting.
Gotta give you kudos for explaining his behavior as well as you did. It's refreshing to see a person wanting to understand why the dog is behaving the way it is, instead of just wanting to change the behavior.
Hondo Von Dopplet L Bauernhof "Hondo"- GSD
Lilie's Tug McGraw "Tug" - Golden Retriever
Maggie - Mini Dachshund (Rescue)
Lonestar Pivo - Texas Blue Lacy
Ashe - Barn Cat
Katie / APHA