Let him know that you are with him: Regardless of whether you live together or not, the fact that a man knows that his partner is with him is something super valuable to him. From the morning you send him a message with a “good morning” or you call him while he is on his way to work to wish him a good day or know that he has an important presentation that day and wish him success in it, it is something that does not have a price for him. Of course, it is not just that you say it to him in the morning and the rest of the day you disappear from his life, that there is some other sign that you care about him like knowing if he already ate, how is his day or things like that, is something that men truly appreciate and makes them feel special.
A little understanding: When he tells you that he does not have the desire to go out at that moment, that he had a bad day for something that you are not to blame, the least that he will expect is that you understand him and not that you get angry or think about things like “because it’s not my fault and we were supposed to go out, so you go”, that kind of thing can make him feel very bad. If he knows that he has understanding partner you say something like “do not worry, we’ll see each other another day” or “okay, calm down and we’ll talk tomorrow”, however, do not stop offering him your help so that together with the previous point, knows that you are with him, but if he does not want it in that moment, understand him and respect his decision.