companionate

adj

1. (historical)Designating a proposed type of marriage (or other partnership) in which the partners plan to have no children and take on no legal obligations to one another.
2. Friendly, companionable.
3. Pertaining to a (chiefly romantic) relationship that emphasises companionship and mutual respect.

   “Gradually it evolved from an economic enterprise to a companionate one—a free-choice engagement between two individuals, based not on duty and obligation but on love and affection.”