Kay

“If you cannot do it to your neighbor, by God then you cannot do it to your wife or sister in Christ without breaking the Law.”

pinklight,
I’ll add to that – “For if because of food your brother is hurt, you are no longer walking according to love. Do not destroy with your food him for whom Christ died… But whoever has doubts is condemned if he eats, because the eating is not from faith. For whatever does not proceed from faith is sin.” Rom.14:15 & 23

There is no qualifier given for wives. If a wife cannot do something in faith that her husband asks of her, then it is sin for her. Even if she is wrong in her understanding, if she cannot do it in faith, it is sin. Verse 12 “So then each one of us will give an account of himself to God.”