Diane Vaughan said this quote

Mourning is essential to uncoupling, as it is to any significant leavetaking. Uncoupling is a transition into a different lifestyle, a change of life course which, whether we recognize and admit it in the early phases or not, is going to be made without the other person. We commit ourselves to relationships expecting them to last, however. In leaving behind a significant person who shares a portion of our life, we experience a loss.