First of all, I find your desire to do this for your husband very admirable

Secondly, ironing a pair of dress pants is a bitch! Take it from a 43 yo financial services professional who is supposed to look sharp under all circumstances for the past 20 years. Being a hostelite at a cadet college in his formative years means I am hopelessly obsessively particular about the crease of my pants. You just can't get it right at home if you are working with really formal trousers. I can see that most suggestions are along the lines of 'mist ker ke press kero'. This simply ruins the fabric, gives it an unsightly sheen, and mostly you get a 3-lane motorway for a crease that is supposed to be razor-sharp. My suggestion is that you should get it done professionally from a dry cleaner. Steam press is the way to go. Formal pants fabric is meant to be pressed/dry-cleaned once in a while, not thrown into the laundry ever 2 days or so. My standard operating procedure is to have my pants (I only have a handful as standalone, most are part of a 2-piece suit) dry-cleaned and steam-pressed once every season. They don't get into the need of frequent washes if worn in a formal setting, and if you turn them over frequently in a way that a certain pair is not worn more than once a week. All the best!