1 Corinthians 7:34
34 There is a difference between a wife and a virgin. The unmarried woman cares about the things of the Lord, that she may be holy both in body and in spirit. But she who is married cares about the things of the world—how she may please her husband.
If you remember way back in chapter five, Paul was addressing some immorality that was going on in the church, and he has continued to deal, indirectly, with that issue in chapters six and seven. He is writing about married and single life as it ties into the original problem in chapter five.
Paul was anticipating changes coming to the nation of Israel, and indeed in A.D. 70 just a decade later, the Jews would be dispersed throughout the world and life would never be the same, and they would not exist as a nation until the year 1948. So maybe, Paul is saying, it might be better to not be married with the turmoil that is coming. But, he knows for many, this would be difficult, if not impossible.
There is a difference also between a wife and a virgin. This is a clear statement, there is a difference between a married woman and an unmarried woman. Paul gives the same advice to women as he did for men. It is easier to serve the Lord as a single woman than as a married woman.
It is not, nor should it be taken as a sin that a wife works to please her husband. The role in marriage is for a husband to please his wife and the wife to please her husband. If couples spent more time pleasing the other person, rather than their own gratification, we would have happier and healthier families.