As HoH, you must take care of your TiH, it is their place to submit to and serve you, but you have a duty of care.

Please do not make the mistake of taking advantage of your position; they are not your slave who you can take for granted.  It would help if you never forgot how special the gift of submission is.

Give your TiH a day off and treat them to a massage, pamper day at the beauty salon.

Surprise her with flowers, meals out or even just a spontaneous hug and “I love You.”

You do not have to buy her gifts continually; that is not what she wants, and she wants you to acknowledge her efforts and show how much you appreciate and lover her.