She added that girls will often intentionally display some cleavage if they think their boyfriend is upset to see if he notices. If he doesn’t, then it’s a clear sign something’s wrong. So, there you go!
I would say that is so absurd!
It doesn’t operate like that! 
Honestly, I think she just wants you to notice her breasts, not gonna lie!
It’s mainly about sexual biology, but culture plays a role too, and not everyone reacts the same way.
Begin to question your own interests. You’ll find that many of them aren’t really based on logic. You simply enjoy them because that’s how your brain is set up.