Please pay special attention to verse 15. This is my answer. She is not bound in these circumstances.
I Corinthians 7
10To the married I give this command (not I, but the Lord): A wife must not separate from her husband. 11But if she does, she must remain unmarried or else be reconciled to her husband. And a husband must not divorce his wife.
12To 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. 13And if a woman has a husband who is not a believer and he is willing to live with her, she must not divorce him. 14For 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.
15But if the unbeliever leaves, let him do so. A believing man or woman is not bound in such circumstances; God has called us to live in peace. 16How do you know, wife, whether you will save your husband? Or, how do you know, husband, whether you will save your wife?
Good point. But you didn’t answer my question.