Just that simple. Show him and tell him you appreciate him. Even if it’s a wake-up text, or he grabs you a drink without you asking, tell him how much you love it and how happy it makes you. He’ll probably do it more often, as well as other sweet things.
If you feel under appreciated, kindly let him know. I’m sure he’ll start to do things for you in return. Since men aren’t too good with verbalizing thanks, take his lovely gestures of a spontaneous neck rub or feeding your shared pet cat as a thank-you.