Should he try not to have children with his Christian wife?

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Check below answers in case you are looking for other related questions:
Her husband does not want more children but she does
If she calls her husband to bed and he refuses

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Related Answers:
Her husband is weak – can she put medicine in his food without him knowing?
Obeying one’s husband comes before obeying one’s parents and siblings
She lives with her husband’s family even though there is a separate apartment available
Her husband does not want more children but she does
If she calls her husband to bed and he refuses

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