Keeping your feelings to yourself only makes it worse, but it does seem obvious that you cannot express things to him. He doesn't seem like a top quality person. It seems you could do better than him.
Sometimes he just makes me feel like i'm just not good enough or pretty enough for him...i told him about my feelings but he sometimes don't understand me and he takes it the wrong way..so he gets really mad...So i just keep my feelings to myself cuz i can't talk to him without him getting really mad or tells me to stop feeling that way..
so its still consider cheating if its a porno cuz i looked it up its call pornhub and theres a live chat web cam..he doesn't know that i know about it.
Make friends here. Make friends where you can. You deserve better than this. If I had a gf and she caught me cheating on a webcam, I would expect her to beat me senseless. Men like that just erk me!
Is the shaking due to nervousness and being afraid or from the depression. Having no friends or people to talk to in your situation can be very stressful and of course harmful from what you say.