Last Christmas I gave you my heart

Whether it's Wham or Taylor Swift, you may have heard these lyrics this season:

=====================================

Last Christmas I gave you my heart
But the very next day, you gave it away
This year, to save me from tears
I'll give it to someone special

=====================================

Let's look at this from the recipients point of view...

Last Christmas...
You really opened up to me and showed me who you were...
Your fears, your dreams and you gave me your trust.
And on December 26th...
Boxing day...
The VERY next day...
You say that I somehow took your love...
And gave it to another person?
Did I sleep with them?
Did I make a mockery of our love?
Are you kidding?
What do you mean?
So...
And now...
You tell me, that in the next five days until the New Year...
You are going to go fall in love again?
Are you unstable?
Are you stalking me?
And when you tell me that you are going to give it to someone special...
Are you insinuating that I was not special enough in the first place?
And if I wasn't...

THEN WHY DID YOU GIVE ME YOUR HEART?