My husband only actually buys lunch out once per week (he spends about $5 a week on that). The other days he eats his homemade lunch at his desk while working and then goes out with his work friends, and just sits with them to talk and drinks water. Sometimes if they go to a Mexican place he eats the chips n salsa or sometimes his friends can't eat all their food so he gets their fries, etc.
We did this as a way for us to save money but he is still able to get out of the office and have non-work conversations. Maybe something like that would work for your husband? I also used to go eat my packed lunches in my car when I worked a stressful lunch, and I would read at the same time.