Mixed marriages and disparity of cult
Through ecumenical dialogue Christian communities in many regions have been able to put into effect a common pastoral practice for mixed marriages. Its task is to help such couples live out their particular situation in the light of faith, overcome the tensions between the couple's obligations to each other and towards their ecclesial communities, and encourage the flowering of what is common to them in faith and respect for what separates them.
Source: Catechism of the Catholic Church (Vatican.va)