He lies to you about watching porn because he knows you don’t approve of it, and he doesn’t want you to disapprove of him.
That said, what you might want to know is how often he watches porn and if it’s an interest or an addiction. Lots of men like to look at naked women because they are usually visual creatures, and appreciate a woman’s body and sexuality. It doesn’t necessarily take away from the other good qualities you describe him having.
If you can open your mind and, assuming his porn watching is amateur level and not something he’s addicted to, agree to disagree on this behavior of his, you may find a place to connect with him so he doesn’t feel the need to lie, and you can accept him (warts and all), while not approving of everything he does.
I hope this helps. 🙂