The bible passages
Exodus 20:17
You shall not covet your neighbor’s house. You shall not covet your neighbor’s wife, or his male or female servant, his ox or donkey, or anything that belongs to your neighbor.
and
Deuteronomy 5:21
You shall not covet your neighbor’s wife. You shall not set your desire on your neighbor’s house or land, his male or female servant, his ox or donkey, or anything that belongs to your neighbor.
both talk about covet/desire. Also, every version of the ten commandments (at least the ones I came across) forbid in some sense the desire of your neighbor's property and/or wife.
In this context, is the desire forbidden or just acting upon the desire?