If you think the treats are the biggest problem, I suggest you give your DH a little bowl of green beans and cut them up into tiny bite size pieces and tell him that he can feed them from that bowl only. I know I had to explain to my fiance (especially since our dog before my girls was 135 lb garbage disposal in a bullmastiff's body) that they don't appreciate a tiny bite any less than a big chunk. I said look at your pinky nail, now half it. That's an appropriate size for a treat. I think the visuals help.
I know he just loves to feed them. Before he puts dressing on his salad, I'll see him pull out some carrot chunks for the girls and set it do the side of his plate, LOL!
I've never been a free feeder, and I know at least one of my girls would eat and eat and eat if allowed to. Also, you don't necessarily need to feed the amount recommended on the bag. After awhile, you will figure out the appropriate amount to feed to the body condition you want. I know I feed my girls substantially less and they maintain their weights. They are a very lean 10 and 12 lbs, mainly due to all their activity, but I also know if I were to feed them the recommended 1+ cups of food total a day they'd be huge. I'm actually a fan of the raw diets and they do very well on that, but when I do feed them kibble they only get 1/4 cup in the morning and 1/4 cup in the evening mixed with supplements and salmon oil in the am and coconut oil in the pm per the vet (point being I know the oils add some calories). They do get treats throughout the day too. I feed a higher protein kibble, which typically does require less food than some of the lower protein kibbles, but nonetheless you may be feeding them too much of their regular food as well. How can you tell who eats what when you free freed? Or can you really tell?
Is doggie daycare an option? Do you think they'd be more likely to get up and get moving around other dogs? When I was working full-time and they went to daycare everyday, Rory couldn't keep weight on her and got so boney but with muscles since she probably never stopped chasing those tennis balls, so I did up her meals slightly (and they were already eating a "lunch" at daycare too) after a clean bill of health with the don't let her lose any more weight warning from the vet.
My beasts can easily walk 4 miles with us (when it isn't hot out like it is now), so maybe you could increase the length of your walks too, weather permitting. They also do a nightly game of intense fetch for 25 minutes straight.
