1 Corinthians 7:3-7

The husband must fulfill his [marital] duty to his wife [with good will and kindness], and likewise the wife to her husband. The wife does not have [exclusive] authority over her own body, but the husband shares with her; and likewise the husband does not have [exclusive] authority over his body, but the wife shares with him. Do not deprive each other [of marital rights], except perhaps by mutual consent for a time, so that you may devote yourselves [unhindered] to prayer, but come together again so that Satan will not tempt you [to sin] because of your lack of self-control. But I am saying this as a concession, not as a command. I wish that all the people were as I am; but each person has his own gift from God, one of this kind and one of that.