I'm sorry about your situation OP. That is very devastating
Like everyone here has said, make sure you get tested, forget the money, and make a clean break to start your life over. He's a jerk, plain and simple. Leave him to his filth. He'll get his.
As for the Nigerian men sterotypes, while being Nigerian myself, I can see where these sterotypes emerge from, I will say that all of them really aren't like that. As someone mentioned, it is the most populated country in Africa= normal a*hole men stats x large population of men= greater likelihood of you meeting an a*hole man. A cheating man, is a cheating man, no matter where he is from. So, please don't let this be the reason that you eliminate all Nigerian, African, or Foreign men in general from your list.
BUT as a warning to all of you, please please please take heed to warning signs. From what i've noticed, the women who do become affected by such situations don't see them. So here's my list based on what I've noticed & seen first hand
If your foreign man, no matter where he is from:
a) has cheating friends (this is for all men in general)
b) frequently travels to his country of origin & never invites you along,
c) faithfully speaks his language on the phone & never lets you speak to any supposed family members that he's speaking with (One of my uncles is married to a non Nigerian, and out of respect for her, makes efforts to speak English on the phone when he can so she doesn't feel out of the loop or at least let's her know who he is talking to)
d) has a very "you are the woman, and I am the man" domineering attitude,
e) has a mother who doesn't want to speak with you and is in the other country,
f)always seems to make requests of you to do things for him or lend him money (again, all men)
g) does not have citizenship
Please please plllllleease let it go. 9 times out of 10, he will play you and leave you hurt. It always saddens me when I hear about these situations, but alot of the times, the warning signs are there. Many men, no matter where they are from, are players & cheaters. The signs that you might have to look for just might have to be different depending on their culture.