Regulus/Sirius
Still, I don't understand. Apparently her family is not 'unfortunate', not my word, which I'm assuming to mean that Narcissa likes them enough. She's smart, she knows about pureblood tradition and lineage (again according to Narcissa). You have married someone who's perfectly acceptable if you just WARDED your comments.
Again, you can have all the orgies in the world. Just keep them secret.