The term mixed marriage refers to a union between a Catholic and baptized non-Catholic.
United States Conference of Catholic Bishops

Your parents may be concerned and offer advice about your marriage. Listen respectfully, but make your own decisions.

Focus on the similarities of your faiths, not the differences. Develop family faith traditions that incorporate your religious practices; praying before meals, religious symbols, attending services at each other’s church.

Consider attending adult education classes or Bible study groups together. It will help in understanding each other’s faith and will enrich your own faith.

It is easy to just stop going to Church, rather than work through the issues of how to worship together. Some couples go to the Catholic Church on Saturday evening and the Protestant Church on Sunday. Some couples prefer to worship separately, and then share what they gained from the service with each other.

Although you may want to put off making these decisions, it is important to determine how you will share your faith with your children before you are married. Although the Catholic party does promise to do all in their power to raise their children Catholic, there may be serious obstacles to fulfilling that promise. Preserving the marriage bond is of paramount importance in an era when divorce rates hover around 50 percent. It seems obvious; therefore, that the phrase, ‘to do all in my power,’ is not to be taken so absolutely that it would jeopardize the marriage itself. It is vital that children have some religious foundation. It is unrealistic to expect a child to choose a religion when their parents find the decision a difficult one.

Prayer binds families together. It could be prayer before meals or bedtime. Reading the Bible and memorizing Scripture verses is a common practice. A line from the Prayer of St. Francis should be the motto for all mixed religion marriages: “O Lord, grant that I may seek not so much to be understood as to understand.”