Your most important role is to continue to love your husband and any children that come into the relationship. Mother and daughter-law conflicts can be very real and damaging to that relationship, and obviously what you are most trying to avoid. It is her son who best knows how to deal with his mother, especially when it comes to explaining differences and similarities in Faith.
He already made the difficult conversion choice and knows the points of conflicts between family and the life he has chosen, and undoubtedly feels the pain more deeply than he lets on.
My brother was wise in his choice of wife. She did not convert for his sake, nor did he ask that of her. My parents in saying, “She has the strength of her convictions” armed me with a red flag concerning future relationships. Yes, she is now a devout Catholic by personal decision.
I would be reluctant about pushing my faith. Instead, let her see how much you and your husband love one another, how committed you both are to your own relationship.
Fulton Sheen, in his program on evangelization, pointed to the importance of looking for similarities. Pope Benedict XVI called dialogue, “Communication across differences.” It is easy to see the conflicts in any relationship. Where do you and your MIL agree? There is little need to get into theological discussions.
Do you have religious statues? My mother responded to this question by asking the other person with they kept family photos. The Saints are part of the family. Church is community. That is not far from what many of our non-Catholic brothers and sisters mean when they talk about fellowship.
Get a copy of the Didache Bible as well as the Catholic Answers Bible. Both will refute many of the unfounded beliefs that non-Catholics have regarding the Catholic Church. Didache simply means teaching, and the Didache Bible has the added benefit of being the Revised Standard Version.
While the NAB is used as the primary source for liturgical worship in the United States, the RSV is most commonly used by our non-Catholic Brothers and Sisters. The Didache Bible provides commentary throughout as it links Scripture to the Catechism of the Catholic Church.
Our Daily Bread, an non-Catholic publication provides a daily Bible in one year reading guide. When my youngest brother died, I inherited his Christian Almanac, which also provides a one year reading guide across the top of each daily page. Each date give events in the history of Christianity. For instance, the Puritans fasted on January 15 to atone for the Salem witch hunts. It only takes 15 minutes a day to read the Bible in one year. The more you know about your own faith, the less your MIL will be able to dissuade any member of your family.
