I'm going to kiss my wife on the forehead when I leave for work before she's up. She pretends she's asleep but I'm pretty sure she's actually awake.
Why would you want to kiss your wife while she's asleep?
I do it because I don't know what else to do. I'm afraid of her.
Kissing your spouse is normal and accepted behavior as it shows that you are affectionate towards them and that is good. However, if you can only kiss your wife while she's asleep because you're afraid of her, then there are issues with your relationship. You should talk with a couples counselor to find ways of being affectionate with your wife without being afraid.
You don't seem to understand what I am going through.
While I admire that you want your relationship to last, I do not think that it is healthy for you to be afraid of your wife as it can be very stressful and would make you very anxious. If you can't talk with her, try to talk with someone you trust on what you can do so that you are not afraid anymore.