You may add a couple in one single dossier or use separate - but linked - dossiers for each spouse.
Use a Common Dossier for a Couple
It is usually more practical to use a single dossier for a couple. In this case, chose the title "Mr and Ms". If the couple uses the same family name, you can add both first names in the corresponding field:
If the family name is different, you can add the spouse in the "Complement" field:
Use Separate Dossiers for Each Spouse
In some situations, you may prefer to use separate dossiers for each spouse. You may link the dossiers with an appropriate relation, e.g. "Spouse1 - Spouse2". This method only makes sense if you're not addressing both spouses at the same time.