Esther, have you told your parents about this man? I know you said you told your friends, but didn't know if you had told your parents. If not, as much as you may hate too, and may be frightened to, tell them (unless of course, they are abusive. But I'm assuming they are not.) They may be able to help you to stay away from this man completely. Your parents should be your first line of defense, not your last. And that is because their job is to protect you, while you are still young. Yes, you may officially be an adult now, but, you are still so young, that you may not be aware of many of the dangers out there.
By the way, this guy sounds very much like a friends ex BF from a long time ago. At the time, we were about 6th or 7th grade and he was about a senior in High school. She kept trying to break things off with him, but he kept manipulating her, saying things like "I'll die if I don't have you" and what not. The only reason he did this was because he only wanted to have sex with her.
I'm afraid you may be in for some rude shocks, and not because he is from another country, but because of the very way the whole thing is going. One of the biggest scams are from people who claim to be from another country. They pry on the naive and innocent, and convince them to send them money. And some, who are really from other countries, only want a spouse from said country, for only one thing: a green card. Not everyone who meets someone online from another country, is going to be a fraud. But the way your situation is, I'm almost 100% positive he is.