I would say communicate. There has to be a reason for the sudden change in his behavior. Don’t jump to conclusions either. You know your husband is there something legitimacy going on for him to prevent it?
There’s a good possibility that he isn’t keeping track on when the two of you have gone out last. Always communicate with him to see where he is. Does he have to do all the planning? You can’t leave all the dates on him, you too can plan and execute some as well.
Stress is the number one thing besides laziness that would allow a man to not think of a missed date night. If he’s stressing over anything such as finances, jon concerns, or the family’s overall plan of action expect him to miss the mark. Wheel him in and set his heart at peace by just asking and not attacking him about date night. Come with what you want to happen as well as some suggestions on where or what you would like to go and do.