In the true spirit of sharing something of life...
People come into your life for a reason, a season, or a lifetime.
When you figure out which it is, you know exactly what to do.
They are there for the reason you need them to be.
Then, without any wrong doing on your part or an inconvenient time, this person will say or do something to bring the relationship to an end. Sometimes they die. Sometimes they walk away. Sometimes they act up or out and force you to take a stand.
What we must realize is that our need has been met, our desire fulfilled; their work is done. The prayer you sent up has been answered and it is now time to move on.