Guys... please answer this honestly??

I am really curious about what a man thinks and why?!

** In a relationship / engaged / married...

.. Have you ever lied to your partner about not looking but in actual fact you are looking at that girl / woman....??

.. Have you ever thought of that girl / woman when your with your partner with whatever you are doing....??

Is it jealousy.... Childish.... Over reacting.... ???

Nobody is perfect but if you do really "love" that person why lie and just love the attention when your partner feels hurt and confused...