The thing is, if they've now been declined a visa then what insentive does he have for staying in a relationship with her? He might as well go and find someone else now, surely?
I know someone in this exact situation, except she has been with her Nigerian husband for over six years, travelled to see him, went back to Nigeria to marry him, and everyone in her circle of friends told her he was only after a visa, not least because she has numerous health problems etc and no money or any prospects.
However, five years ago he came to the UK after her MP intervened to secure him a visa. He is working, has been to college to gain further qualifications, and most relevant, hasn't disappeared into the sunset.
It's becoming increasingly more difficult to believe that he's only in it for the visa even though one's instincts scream that there must have been another motive.
If he'd disappeared after six months of entering the UK everyone would have said it served her right for being so gullible and falling for a scammer who clearly just wanted to take advantage. And actually, the message behind that goes so much deeper, because it essentially says that no man of that age and caliber would obviously go for her in her situation. Except now that he's stuck around for the long hall we don't see people coming out to say that they must have been wrong to make the assumptions they did. At what point does one change one's view? Look at e.g. Bruce Forsyth's last wife. She was significantly younger than him when they got together, he in his 60's and her in her 20s I believe. And I imagine that most would say that she'd snared an older celeb for his money, and yet they stayed the distance.
I don't believe that the 27 year old who had Mick Jagger's baby loves him any more than the 27 year old who is apparently with this woman. And yet there's always a chance that one could be wrong, and while there's a chance, people will keep taking these steps, and in some cases they may not be the ones who are wrong.