People use contraceptives because they want to split God's gift.

They want pleasure, without responsibility, without the full fruits that God wants for them.

They think they know better than God.   They're not willing to deny themselves pleasure in order care for their wife, etc. 

They believe they deserve pleasure on their terms.

Would that they would learn of other forms of growing in friendship with their spouse...better conversation, walks, puzzles, sharing, creating games, serving others...no, they stop short.