I think another factor is the widespread almost-sexual desire that many women have about being "owned" by some "dark", mysterious, exotic, manly (i.e. chauvinist), passionate (i.e. unable to control his outbursts), possessive man who can treat them in a firm but just way (at least initially) and make them feel special (at least initially).
So who's the best match for all that?
Guys like the stereotypical Sicilian gangster, or the stereotypical middle-eastern Muslim ^_^
Do you know what's fascinating to me? Of all of the white male converts I knew over the years, only one was married to a white woman who was not from an Eastern European Muslim background (and of those, I knew of three). By and large, these self-hating men married women from Eastern backgrounds. Possibly because as privileged, straight white men they had a fantasy of owning the exotic, but more likely than not I think that Muslim communities - and perhaps this is a North American thing only - have a way of inculcating hatred of whiteness into white Muslims (while simultaneously fetishizing it). And there is this thing about having children with these spouses - male or females - and then insisting, to the point of ridiculousness, that one's children are not at all white.
This seems to especially be the case in the Hamza Yusuf type circles as well as others... a lot of hatred & fascination with whiteness and there was many a time when I listened to people -some of them white - rail on at others present about how being white is never, ever right - as if one could change it! I once said, 'But if allah made a person this way, then how can it be wrong?' and the person was temporarily silenced before once again continuing his tirade against whiteness. I guess 'surrender to allah's will and accepting his creation and qadr' ended, for these people, where there isn't enough melanin in the skin. This in NO WAY negates white privilege, etc. I'm just saying a lot of these white Muslims - esp the men in my experiences - have a lot of hatred towards themselves and their white skin and they demonstrate it by making sure to NOT marry white people - so their children are not 'white.'
Another thing I have heard a few (just a few) white Muslim men say about why they don't marry white women is that white women have not been trained up enough by our society to be properly submissive and to be good housewives, whereas women from traditionally Muslim families have been (and you also hear this sort of self-hating shit from some Black brothers as to why they prefer a wife from overseas vs a Black woman).
I know a few women who converted after marriage - most of my friends were actually converts and most of them converted while single and some remain thus. Most of them had the usual 'I wanted to understand him more so I started reading the quran and blah blah allah is one and that really hit home with me' story. Believe it or not, I know more than a few women over the years whose husbands actively tried to discourage them from reading quran or learning more about Islam. They had to do it on their own and without his knowledge or encouragement or support. So the man was already married to them - and one doesn't have to be Muslim to be into a sub/dom relationship. I know one woman who converted while in a sub/dom relationship -- with a Buddhist. It was about as strange as you think it would be.
Topic: What do you think makes alot of women...