When a relationship ends, ANY relationship...there is always gonna be a letting go phase.  Sometimes people make it easier than others and some you can't imagine not having.  Either way, it is a loss.  A loss that must be dealt with!  Just because we might not have placed high importance on it, doesn't mean our lives were not changed because of it. 
The same goes for who I was to the other person.  I may have been very little involved or maybe on a daily basis, but I was involved.  I try to never walk away from a relationship thinking I meant nothing.  That kind of freedom is why so many believers end things so easliy, and sin runs so deep in our church family.  That is the very reason Christ died, so we may reflect who He is, in EVERY action we make.  Now, do I really make every move count? No! My past and the hurts I have suffered and the wrongs I have done, remind me all the time of how flawed and weak I am.  How imperfect my life is!  I don't consciously think of them, but I have impacted every person I come in contact with (good or bad), and every person I have come in contact with, has influenced my thinking.
I have to remind myself that everyone from the bible other than Jesus....was imperfect.  So many failed....but with Christ......they prevailed!  God's will was carried out, but not because of who they were, but who God is!!!  I relate to Peter....he had a temper! I relate to Noah who got drunk (and probably acted stupid)!  I can relate to Gideon who was insecure.  I can relate to Thomas, who was a doubter!  I know what God really wants me to see, is that HE pushed through those thoughts with HIS word and instruction!  HE DID IT, NOT THEM! 
It is impossible to let go of the relationships that have caused us damage and the actions that have hurt others, without the renewal of our minds and who God wants us to be! So as scripture says....push on, move forward until the day of Christ......................Blessed be the day of the Lord! Greater is he that is in me, than he that is in this world.
ROMANS 12:1-2 
Therefore, I urge you, brothers and sisters, in view of God’s mercy, to offer your bodies as a living sacrifice, holy and pleasing to God—this is your true and proper worship.  Do not conform to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is —his good, pleasing and perfect will.