This isn't a 'man' issue. I can tell you that as a man, and as a 20 year depressive person. Depressed people are very sensitive to how they are treated, and can very easily take the way someone treats them or talks to them, in a wrong light. Even if you mean well. Being depressed makes you feel vulnerable, and people being deceptive, even for good reasons, scratches on that vulnerable feeling. They feel weak and powerless, and when someone goes behind their back to 'help' it only makes them feel that you see them as weak and powerless as well.
Also, many depressed people want to hide it. And when someone see's it, it increases that sense of being vulnerable. You have to take your husbands reactions, not just this one, but how he acts in general, the same way you might to a person who has a really bad cold or flu. They feel bad, and it makes them grumpy and overreact to things that might not normally bother them. Not because of you, just a reaction to how they feel. You husband is in a similar position, except much worse. Much of how he reacts is less about you and more about him. I know its hard, but the less personal you can take it, the easier it will be to deal with him for you.
Remember, along with being vulnerable, depressives have this internal apathy, and lack of belief that anything will help. You cannon approach a depressive person by being pushy, sneaky or deceptive. And you have to realize that most of your attempts to be a positive encouragement will not get through. But that doesn't mean not to try. Some will get through, it just takes a while for it to 'build up' internally, enough to cause them to act to get help.
So right now compassion, empathy, patience.. not being deceptive, even for good reasons, and not being frustrated and pushy, are the best you can do. Along with not taking things personally. Even though you know you did things for the right reason, he will not see it, and if he does, he won't be able to admit it to you, or even to himself. So best thing is to apologize, and promise to never go behind his back like that again. Think about a time in your life when you felt very vulnerable, and how every action from someone was examined. You got past it, but a person with depression lives it every day. Just keep that in mind and how you would want to be treated when you feel vulnerable.