Death shocks. It is such a finality. The dead person is no longer doing anything, so your consciousness cannot be distracted; it might dive into memories but it cannot be distracted. And, sooner or later, you wouldn't know but you would be propelled out of that window of memories.
I wonder if relationships can be pronounced dead when the protagonists - who were once a part of the relationship - are alive. Perhaps the fact that the other person is alive and doing something always has the potential to pique your curiosity, to distract you or to make you go through some obnoxious emotions.
It is strange but sometimes death (of the other person) could be a far better balm for an aching heart. No, of course, to wish the other person's death isn't the suggestion. But it's a comment on the nature of death.
Sometimes, just the awareness - that your consciousness can feel distracted by those you were involved with earlier - could be liberating. Perhaps it could help you to consider the other person dead and to live as if the other person is dead. That is, until you inadvertently stumble upon him/her again. When FB, parties, social occasions, events, arenas of public entertainment, media-presence etc bring him/her back into your consciousness.
So? Live out the bout, what else! And, better than that, train hard. Real f***** hard! So hard that you almost nearly die.