let it linger

Accepting nothings going to change in a situation where your relationship/ situationship is slowly depleting or you are being mistreated but you don't do anything about it due to loving the person too much. “To stay too long in a situation due to reluctance to leave”.

A known saying from The Cranberries song “linger”

“She loved him too much to end the relationship so she just let it linger.”