Lunches need not be complicated or expensive or even time consuming. Just make a little bit extra throughout the week and assemble leftovers on Sunday night. Its that simple. The only caveat for this strategy is that you actually are making meals your spouse likes and that your dinner recipes can be expanded easily to increase the quantities. Get 1 or more wide-mouth Thermos containers.
Blue ice is great for keeping stuff cold.
They'll save space and thaw by lunch. Pack bun separately in Zip-lock bag. Include paper plate. He can assemble on-site. Baked beans in another Thermos makes a good side.