Grieving a friendship lost

So I have been realizing lately that I am losing a friend. It is kind of a weird situation. I have been throw a lot with this person; but the one thing that I have come to realize is that the relationship is a co-dependent one. I am this persons friend when they need me or when I pursue them. There is not much effort on there part to be my friend nor are they the first person to answer the call when I need them.

The odd thing is that while I am sad for them and I am grieving the loss of this friendship I also know that it is in God's hands and I have a peace about the situation. It is really like the separation is God's plan. I know that may sound funny; but I have come to realize that there are people God puts in our life for a season and only for a season and then there are other people that no matter what the situation or what life circumstances there are will be a part of it. 

Relationships are so weird; I am glade God has them figured out.