I am so sorry.
I definitely agree with the posters above. Has your wife always been so cruel towards you, or did this begin sometime after you got married to her? Were you in abusive relationships before she came along? Was she??
The examples that you've given of recent remarks just blow me away. I wouldn't be real eager to do whatever I could to please her either. There is no evidence of possible rewards for taking care of yourself for her ~ she treats you crummy either way!

The important motivation to grab a hold of & hold onto is YOURSELF. You deserve better!
Take care of yourself to make yourself feel good. It does take some effort at first, but soon, the feel-good hormones do kick into gear and reward you for caring for yourself. Go work out, to relieve stress and anxiety (it also helps fight depression). Take daily showers mindfully. Let yourself enjoy the sensation of the warm water coming down upon you lovingly. Try to look at it as though the water is washing your mind clean. No problems or troubles weighing on your mind ~ you are free to simply enjoy the scent of soap and shampoo, the feeling of your hands massaging your head with shampoo and feeling the soap slither through your hands onto your body, the relaxing sound of the water hitting the tile, hum or sing a song that you enjoy, etc. Those 2 things are great relievers of stress and depression!
Another tip: work with a T (therapist) to get yourself into a healthy state of mind, and stand up for yourself. If you really feel that there is some love in this marriage, do what you can to get her to attend couple's counseling with you. Otherwise, you are way better off without her. Your wife's frequent put-downs and snide remarks need to stop either way.

Very best wishes to you & welcome to Psych Central!