It would seem that death is the final termination of any relationship, yet it can vary depending upon the length and depth of the relationship. Some people have found their partner has been with them so long they simply seem to hear and feel them near even after they have passed. Those with a partner suffering from illness may find relief when a partner passes on, or they could simply be too emotionally drained to feel much at first. Experiencing profound grief can come at any time, but a fatal accident or unexpected loss of a partner can trigger it.
Death at any age is an absolute for those who go on living, yet a partner need not be deceased for the other person to feel deep grief. The person who chooses to leave the relationship may not have had a large emotional investment, but they could have been everything to the person they are ditching. That person could find anger and resentment taking a back seat to feelings of grief. Their loss is one that feels the same as death to them, and they could need counselling to be able to survive and move on with their own life.