1 Corinthians 7:3-4; 1 Corinthians 7:10-14
The husband should fulfill his marital duty to his wife, and likewise the wife to her husband.
The wife's body does not belong to her alone but also to her husband. In the same way, the husband's body does not belong to him alone but also to his wife.
To the married I give this command (not I, but the Lord): A wife must not separate from her husband.
But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife.
To the rest I say this (I, not the Lord): If any brother has a wife who is not a believer and she is willing to live with him, he must not divorce her.
And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him.
For the unbelieving husband has been sanctified through his wife, and the unbelieving wife has been sanctified through her believing husband. Otherwise your children would be unclean, but as it is, they are holy.