Is it wrong that ate my husband's donut?
That sounds naughty. Why did you eat your husband's donut?
Because I was bored and I wanted to eat some donuts. My husband let me eat one of his greasy donuts
As long as your husband was okay with it, then you did nothing wrong. However, it is usually wrong to eat someone else's food without asking them first.
But I am hungry and he had enough donuts.
You should not stress about eating a donut, especially if your husband had more. However, to avoid feeling guilty next time, you should ask first before eating anyone's food.