The One With The Replacement

Everything in life gets replaced and forgotten.
As my "substitute" stepped in today, it is clear that I'm not an exception.
Why would I be?
Her arrival today also meant my imminent departure.
I was shown a glimpse of what life without me would be to my friends.
I couldn't help but wonder how long would it be before I also get replaced in her heart.

My time with her diminishes as days go by.
How many more times can she fall asleep on my bed?
How many more times can I fetch her home?
How many more times can I kiss her and say goodnight?

How can I pretend that everything will be alright when deep down I know I won't be?