This is a great question as it is very difficult to piece together what is actually going on in their marriage and we have to infer a lot into what is said and what isn't said. The part of the play to examine very closely is the beginning of Act II, when we are introduced to Elizabeth and see them in their home together.
Note how Elizabeth starts of the act with an accusatory question: "What keeps you so late?" Clearly the affair that John had with Abigail has eroded a lot of trust between them. However, it is clear that John is also taking great pains to not raise any difficulties between them - note how, before Elizabeth enters, he adds extra salt to the stew and then says to Elizabeth the little white lie, "It's well seasoned." He then goes on to say to Elizabeth, "I mean to please you, Elizabeth", however note that in her response, it is "hard" for her to say "I know it, John."
These are just some examples that comment on the state of their marriage. If you read the full act you will find many more, but it is important to realise that John seems to be trying as hard as he can to make amends to his wife. She, however, in spite of trying to be a good wife, is finding it harder to accept John back. Note what John says:
You forget nothin' and forgive nothin'. Learn charity, woman. I have gone tiptoe in this house all seven month since she is gone. I have not moved from there to there without I think to please you, and still an everlasting funeral marches round your heart. I cannot speak but I am doubted, every moment judged for lies, as though I come into a court when I come into this house!
Note also his somewhat pained remark "Your justice would freeze beer." He clearly feels that Elizabeth is not meeting him half way.