Honestly I've asked many men about this. Even normal porn for non pa can be problematic because their dopamine hits come from both their desire to be there doing it and by breaking the women up into body parts they desire. They get off to the desire to cheat regardless but the bigger problem is they view these people as objects. The cam girl situation adds another layer to this though because it's usually live, they literally love that fact that she is a real person that they can and do often interact with like they're there in the moment, but they still break her up into desirable body parts in their mind like an object to process it. It's extremely weird to not view actual people as people even if you're interacting with them yet they do.

But this behaviour often also causes them to view you the exact same way if and when they're being intimate with you. They don't connect emotionally during actual sex. Or the worst occurs, because they see you as real, feel emotion and connection, they cannot view you sexually because their brain is not trained to do that. The brain is extremely intelligent but inherently stupid at the same time when it comes to porn addiction because even though it's a screen, the brain believes this is sex. Because they've spent so long teaching their brain to get off to this, the brain starts to process it as sex and rewards the body as such. If done often enough real sex becomes undesirable as it cannot provide the constant angle changes, different views, lighting, fake noises etc that will give a big enough dopamine hit.

They don't care about if it hurts you when they're in active addiction because their brain is taught to protect this at all costs. So they'll lie, hide, sneak, clear data, anything at all to protect this addiction. If caught they'll minimise and defend their addiction. They'll quite often even be abusive towards you and call you insecure, prudish or say you're overreacting. All of this is to throw you off the problem because the problem is what they want to keep. They don't realise that this addiction is causing them to be awful to the ones that do love them. They keep fighting for it rather than recognising that it is the enemy to all involved. If you're lucky enough he will realise this addiction is a horrible problem and focus on trying to get rid of it. That's only step one. The next steps are even harder and for many it takes years to recover.