I was hoping to hear from you, but I'll give you a response, and if I am incorrect in my assumptions, you can get back to me by replying on this question thread, and I'll amend or expand my answer.
People who ask a question like this have usually met someone on line who has expressed their love to them much too quickly. They want to know if they are the victim of a romance scam.
The most common romance scam is called the Stranded traveler scam. Here's how it works and the telltale signs of the scam:
You meet a guy on a social networking or dating site and he falls in love with you at first sight. He talks love, marriage, future and forever, before you can even meet in person.
He is everything you always wanted in a man, and you can't believe your luck. Typically, but not always, he claims to be a widower with a son or a daughter. Usually, he claims to have his own business. Most frequently he claims to be an engineer, an architect or a contractor.
Whatever his profession, however, before he can finally meet you he tells you he must travel abroad for work purposes, and he ends up typically in some country that's neither his nor yours. Most often he claims to have to go to Ghana and Nigeria, because these two countries specialize in romance scams.
Anyhow, once there, Mr Perfect suddenly suddenly turns into Mr. Needy, the world's unluckiest guy. He has the first of a series of emergencies for which only your money will do. There's equipment failure , for example, and he can't afford the repair. Or Customs is holding the products he ordered and he needs money to get them released. Or he has cash flow problems and he can't afford to pay his workers. Or he gets robbed of all of his documents and he can't leave until he pays his hotel bill. Or he or one of his family members gets ill and cannot get treatment or leave the hospital until you pay his bill.
There are bunches of excuses like this. They are all lies and they are designed only to part you with your money. Of course, each time he gets money, he assures you that he will pay you back when he returns home. But he never gets an inch closer to the plane, and he never will. He is not who, what or where you think he is. He's a ring of thieves hiding behind the photo of an appealing man.
Once talk of love turns to money with any online romance you have not developed a real-time actual in-person dating relationship with, you are being scammed. Each and every time.
I know that you suspect him. You're wise enough to suspect that nobody legitimate would ever ask you to marry him before ever meeting you and getting to know you in person.
If what I've said above sounds like your circumstances, you've got yourself a scammer. If you're still not sure, please attach photos of him with your reply to this question thread, and I will look for more concrete information if you need it.
If I have convinced you, you need to report this as a crime to your police and to the FBI at their Internet Crime Complaint Center at IC3.gov.