I'll try and keep this short. I'm an atheist and my wife is a Christian. This wasn't always the case though. When we married I was still a Christian. A few months after being married, I completely lost faith and couldn't continue pretending to believe.
She is having a hard time because of this. She is stuck between divorcing me and staying married to a non-believer, both of which are sins:
1 Corinthians 7:12-16
To the rest I say (I, not the Lord) that if any brother has a wife who is an unbeliever, and she consents to live with him, he should not divorce her. If any woman has a husband who is an unbeliever, and he consents to live with her, she should not divorce him. For the unbelieving husband is made holy because of his wife, and the unbelieving wife is made holy because of her husband. Otherwise your children would be unclean, but as it is, they are holy. But if the unbelieving partner separates, let it be so. In such cases the brother or sister is not enslaved. God has called you to peace. For how do you know, wife, whether you will save your husband? Or how do you know, husband, whether you will save your wife?
2 Corinthians 6:14
Do not be unequally yoked with unbelievers. For what partnership has righteousness with lawlessness? Or what fellowship has light with darkness?
As a Christian, what does one do in this case? What is the thought process behind making this decision?