How does one grieve a relationship that never was?

I realized today (with the help of my therapist) that I AM grieving right now.

I am grieving the relationship I will not be able to have with my grandmother.  The relationship that was denied by years of my parents not allowing us to spend time with their parents.  The relationship impeded by distance, both geographically and emotionally.  The relationship clouded by the lies and misunderstandings of years of hurt on both sides, never explained to the children we were, or to the adults we became.

I am also grieving the relationship I have never had with my mother, and which became even more clear to me over the past month, will never happen.  I grieve the painful, incomplete, one-sided forgiveness for abuses heaped-on.  I grieve the human frailty that denies any chance at reconciliation.  I grieve the ravages of disease on a once-brilliant mind.  I grieve the loss of opportunity for my children to connect with this grandmother.

Yes, I am grieving.  I actually cried today for the first time since learning that Grandma had passed away...frankly, it was a relief to cry.