The comment about being safely married is ironic because her husband had an affair and Mrs. Bentley does not want to expose the fact that she knows her husband had an affair.
The social criticism comes from the fact that Mrs. Bentley has to pretend that nothing happend in order to be happy, even though she knows her husband cheated on her.
The conversation at the dinner table centers around Judith, the woman with whom Mr. Bentley had an affair. Mrs. Bentley wants to adopt Judith’s baby, and she has gotten over the infidelity as much as possible for a second chance at having a family.
Mrs. Bentley is desperate. Her home situation has been so bad that she sees the baby as her only escape, even though it is a reminder of her husband’s infidelity. Her comment about Judith and the long farmer precedes the quote about being a safely married woman.
You can never tell though. Sometimes it’s the mild, innocent kind that are the sly ones. A woman usually knows what she’s about. (p. 209)
She says that “to pity her would be to condemn him” and she feels that he is going through enough. Mrs. Bentley does not want to condemn her husband. She wants to put the infidelity behind her and move to a new town. She certainly does not want to confront the idea of Judith marrying and keeping the baby.