porn...and men

Why do some men hide and watch porn when they are in a relationship? And when they get caught they deny it and get all defensive...we have amazing sex but then I go find this shit out...i don't get it...😕 I'm always throwing myself at him but it only happens when he wants it ...makes me feel soo insecure at times bc I had a great body and 9 months ago had a csection and having a hard time losing my belly....and I workout almost everyday