It was 19th century Ireland, not to different from Ireland today.
The wife is allowed to hit you once with the frying pan and then all is forgiven.
What I learnt from watching 3 seasons of Deadwood is that wives would not give and would not be asked to give blow jobs. It was seen as unclean, and doubly so for sodomy. Which is why prostitutes were a necessary evil before men and women could talk frankly about their sexual needs before committing to the rest of their lives together.