Your husband could be experiencing significant asthma symptoms, including “tightness” of his chest, without any outward signs, evident to others including yourself. We recommend pre-medication prior to exercise for people who have exercise induced asthma. Your husband may be using his inhaler preemptively because he has been having nighttime symptoms. In that case it would be understandable why he might be using it. However, if that is the case that he has frequent nighttime symptoms that would be an indication that his asthma is not well controlled. In that case he would be well advised to consult with his doctor about the use of a long-acting inhaled bronchodilator in combination with an inhaled steroid.
When quick relief is needed, 2 to 3 puffs of a rescue inhaler is the appropriate dose. But, if the perceived need is once a day or even 3 to 4 times weekly, the strongly advised therapy should be that mentioned in the preceding paragraph.
I strongly recommend that you and your husband schedule a joint visit with his doctor to get the facts about his asthma and “clear the air” so to speak so that you and he can discuss it in a sympathetic, civil manner.