Porn and Lying

I talked to my husband awhile ago in a non-judge mental manner about his porn usage which was really bothering me. I was honest and told him how I felt and he said he didn't need it to masturbate and would stop. Which meant a lot to me. No I do not have a problem with masterbating the porn bugs me though. Well i found out today that he's just been lying and still watches it anyway and that really hurts my feelings. Why lie to me? Why not just be honest and say you're never going to stop even though it hurts me? At least then that's honest. I feel like I must be selfish or something for feeling this way so I don't want to talk with him about it again. Did I mention my self esteem is super low and I had a baby three weeks ago?