I know your pain! Our problem child, Bo, started presenting with food aggression. I immediately began working with him slowly (small amounts of food at a time, hand feeding, etc) and was making very slow progress. I couldn't figure out why. I had gone over the whole procedure with my husband several times, he nodded and agreed.
The one day an entire bowl of dog food accidentally spilled at my feet. Bo ate it around my feet as I stood there and he didn't bat an eye. My husband approached and Bo suddenly went ape-shit. Then I realized the problem. That jerk hadn't been taking the five extra minutes a day at morning feeding time. Then I was gone on a trip for two weeks, returned and it was even worse.
And THEN (how about father rants while we are at it?) Christmas came and my dad convinced him that Bo just needed, "The s**t kicked out of him a time or two to show him who is boss." I'm ashamed to say, my husband actually let this happen (unbeknownst to me). "Well your way wasn't getting results!" he said.
Poor Bo peed out of fear and cowered for the next week when we fed him. My husband quickly conceded. For his credit, I think he has some fear of his "manly man" father-in-law (who I'm the first to admit is a red-neck hick) and didn't want to appear weak while my dad bashed my "soft" ways.
Husband made repair, is actively with the program and we have almost no food aggression left.