The wording of your question is interesting - does he have a 'big' problem, or do you have a problem with the fact that your boyfriend likes porn?
I can understand your insecurity, and i think it's something you need to discuss with your partner. You certainly shouldn't feel that you have to behave like a fantasy figure in your personal sex life with him.
If your boyfriend is making an issue of his enjoyment of pornography, that needs to be addressed. The fqct that it upsets you enough to post on here means it is an issue for you, and therefore an issue for him.
I can tell you that from the perspective of male sexuality, pornography is not preferable to inticamcy, it is simply different stimulation. A man may like apples, but he also likes oranges, for different reasons.
If this is making you unhappy, then you need to find out his attitudes, and explain yours.
If my use of pronography upset my wife, i would stop imediately - it's not worth hurting someone you care about.
Have a chat with him, calmly, don't accuse, listen, and discuss, and see if you can find a way forward.
Keep us posted.