Razanir,
I can’t answer this question for you. Here’s the reason why: Jesus said, “I say to you, everyone who looks at a woman with lust has already committed adultery with her in his heart” (Mt 5:28). Your question doesn’t cover all the possibilities: when you look at the porn ‘inadvertantly’, are you looking “with lust”? (If so, then you have some serious questions to ask yourself!) When you go to the site, if you know that there’s the possibility that you’ll encounter some pornographic material, do you go to the site “with lust”? Or, at the very least, do you go there in the
near occasion of lust? If so, then again, you and your confessor need to have a serious conversation.
The fact that you’ve posted your question here leads to an obvious conclusion: you
know that there are posts at that site that are contrary to your spiritual health. Ask yourself – is it to your (spiritual) benefit to go there? Does it help your relationship with God? Does it have the (reasonable and foreseeable) expectation of hurting your relationship with God?
If your answers are “yes, yes, no” – and your confessor agrees – then there’s likely no problem. However, if you answer otherwise, then you need to think about whether it’s to your benefit to browse there…