UK Based Guy Laments How His Nigerian Girlfriend Extorts Money From Him - Needs Advice

Hello,
I'm a 28 years Old guy and live in the UK. So I've got this girl and we've been together for four years but she lives in Naija. Her's the problem, I work very hard, like very hard shifts of different jobs just to save up for my future. 

But my GF doesn't seem to get it, she doesn't make any money but lives large, she's a graduate but no job. I have sent money for this and that makeup school but apparently every girl does makeup in Nigeria now so competition is stiff. She doesn't work but buys her friends' aso ebi and travels to other states in the name of the wedding, all with my money. I don't even mind cos I love her, but it's beginning to tell on me cos I recently decided to evaluate how I spend my pay and I don't even enjoy as much as I should compared with how much I work. I have started to lie about how mjuch I earn to her now. 

So last night we was on the phone and she bluntly asked for a steady weekly allowance, that the economy is hard blah bla. I called my brother for his opinion this morning and his only reply was : bro, you better give her cos Lagos boys will give her"
Now I'm scared. I work too hard and I'm scared my money is going down the drain. if I keep giving her money she's never going to find a job, I don't even look as flamboyant as her sef and I don't want to lose her