Express appreciation to your husband and respect his concerns.
By far the most important step is to talk to your husband about this in a way that he truly sees that you appreciate him and that you want to understand and respect his concerns in this area. Tell him, regularly, how thankful you are for all the work he does to provide. And then at some non-emotional time, inquire about this. Ask whether he feels pressure when he sees your shopping bags, or when he knows that you’re spending money on things he might view as non-essentials. If you two have worked out a budget that you’re sticking to, ask him what you both can do to help him feel better about it, yet without you feeling like he’s constantly checking up on you and signaling a lack of trust.