Why does he lie?

[Death Trap™]

I don't think watching porn is really that bad at all and I bet most guys only do it for self-pleasure. This doesn't mean he will actually cheat on you. Since he is a guy, probably he won't admit because you might scold him because your his gf yet he watches porn. Since you said you will let him do this own thing, you should ask him this question "Baby would you ever cheat on me, honestly?" Maybe that would help put you a little at ease. If he does, it would be his loss that he wasn't the one for you. Seeing your picture, you seems to be quite pretty that I hope he treats you right. You know everyone deserves their best. If you ever feel he is suspicious, confront him and ask. Never assume anything. You might be misunderstand and cause the relationship to go under tension. This will lead to trust issues. Good luck.