You can free shape him to lie quietly on a mat when your husband leaves.
Pick out a mat for him to lie on. Have ready a good amount of soft tasty treats (hot dogs, string cheese, left over table meats, boiled chicken etc) cut into very small pieces. Pieces should be about half the size of a nickel. If I were going to train this to your dog, I would keep bags of bait cut up in my fridge for several days in the beginning. If the dog is well motivated by it, you can also use his kibble to train. Either way, if your dog has a weight issue, you need to deduct the approximate amount of the bait from his regular meals.
You will also need something to mark his behavior with. If you have a clicker, great. If not, you can use the word "Yep!" said in a pleasant but clipped tone of voice. If your dog has not learned what a marker means, take 50 treats, and feed them to him in a row one right after the other. Use your marker, and each time immediately feed the dog. So, if you are using the word YEP it is Yep/treat/yep/treat/yep/treat continuous until the treats are gone. Then you are ready to start training.
So, you have your treats and your mat. Start with your husband at home and the dog relaxed. Call him over near the mat, and each time he puts a foot on the mat, mark and treat. Don't say anything. Don't coax him to the mat. Just mark and treat him every time he touches it. If he is having a really tough time with getting started touching the mat, throw a treat onto the mat a couple of times, and each time he touches it to get the treat, mark and treat again. It is important to mark as quickly as possible in the beginning when his foot touches the mat.
NOTE: DO NOT hold the food in your hand. Put it on a table or countertop, and get a treat each time you reward the dog.
Once the dog goes to the mat 3 straight times in a row the first time you put it down on the floor and start to train, move to the next step. Random reinforcement.
Now you are going to begin to SHAPE this behavior that your dog has learned. Now you will click for longer stays on the mat. For all 4 feet on the mat. For any dipping of his head while on the mat. Any sitting, click. You can shape your dog into downing on the mat within a few days if you just stick with it. Remember, no talking during this type of training. Just mark, and treat when you see behaviors that may be an approximation of what you want later.
Keep raising your criteria. Keep your rewards random. Jackpot the dog and give him several treats every once in a while, or when he makes a breakthrough. The more rewards your dog gets while he is on the mat, the more he will WANT to be on the mat. Once he is putting all 4 feet on the mat consistently, start giving him a release command every single time, starting with very short durations. Mark and treat for the release just as you did the other things. Now you are building into him to STAY on the mat until you release him. Again, the more you do this, and reward the dog, and build a reward history with him with this behavior, the stronger the behavior will be. Once he stays on the mat for 10+ seconds 3 straight times the first time you put it down, you can start naming the behavior. Be sure to be using your release command. THIS is what teaches your dog to stay until you release him.
These methods work for any behavior you want to teach your dog. Once you start training this way, it is seriously addictive, and AMAZING the things you can teach your dog. Dogs trained like this really REALLY want to work with you.
Once you have this behavior built, THEN your husband should begin leaving for short periods, with you building reinforcement into his calm behavior on the mat over time.
Good luck.