I honestly believe it's a sign of self hatred, Black men who do not value themselves as men and feel the need to prove it by getting White women to show they are good enough to do so. 
If you love who you see when you look in the mirror, you will seek what is closest to your heart..and that will be a Black person.  If they believe the lies about how inferior they are they will need to prove it otherwise by going into and being accepted by the enemies camp.  Please correct me if I'm wrong...

It's everywhere and some people prefer their own sex.

Since the sex of a child is determined by the sperm of the father; if a male child is truly needed it is SHE who needs to reconsider her choice of mate.  If HE takes another wife, he will make another daughter.  Where are you in the genetics stuff?  Catch up!!  It is the husband who is spouting out the girls, not the wife. 

Very easy marriage, he probably can't have children or the equipment to make them doesn't work so she won't be bothered then he'll be dead by next week anyway and she'll be free again. Hopefully he'll leave her money or open a business for her and she can marry someone young and beautiful.  Hahahahah