In my longest relationships, I have stuck-it out in caring for the person until they had drained all the caring out of me and I had nothing left to give. In the cases where I was rejected, it did take a quite a while for me to let go of those feelings of longing and hoping.
However, I have never stopped truly caring about and feeling love for any of them. They have all been important in my life and I sincerely wish them well. This is where it helped me to distinguish between the the feelings of love and care and the acts of loving and caring.
As I matured and became more comfortable in my own skin, and confident in myself as an independent person, it got easier to let go since I didn’t define myself as being someone’s “other”.
I am not able to relate this to the loss of a friendship, because I haven’t had to end any of those. I guess the hardest was when my mentor and I had a fight and I got unjustly fired. But in that case, anger helped fuel the detachment. I often see people use anger for that purpose, which is why it sometimes seems like people are overreacting – but I think they are simply using the anger as a shield or a wedge to increase the distance when they know in their heads that it’s for the best, but their hearts are torn.