I don't know if this is a naive viewpoint but I've seen and heard of couples where they start off dating when the man is broke but then years later, when he becomes a professional and gains wealth, she is still with him.

I've seen this mostly in Mexico, which is of course a lot more conservative, but are these kinds of women loyal? Or what exactly are they?

They could easily leave the broke guy and go with a rich one but they choose to stay with him until he makes it.