Answer: Companionate
Explanation: Companionate love could be explained as a relationship or love affair which exists between married partners who have been stayed together for a very long time. This type of relationship or togetherness is usually kept alive due to the intimacy created by the length of their being together (usually very long). Because over time, the passion and affection seems to have declined but the commitment and intimacy keeps them together as companions.
Companionate love highlights the type of relationship between Edgar and Esther which is intimate but non-passionate after it has spanned for almost 50 years.