Yet, DLS is partly right--we are all 50% responsible for how our marriages turn out--it is never one spouse who creates an entire dynamic. Even when we think/say we want a particular thing in our marriage, if we don't have the guts to stand up and demand it, then how much do we really want it? You say you explicitly told your second wife you didn't want a sexless marriage--yet, she could probably tell on some level, either at that point or after the sex ended, that you too were not "being honest" about that, since 12 years later you haven't acted on your words.
Take the example of a woman who was beaten as a child by her father, and possibly a boyfriend or two, and marries a man she thinks is completely different, letting him know that she's escaping from a life where she would be beaten. Yet, often as not, a few years down the line she's being beaten by her H. Is she entirely a victim? The beatings, certainly, are not in any way her fault, and are reprehensible. Yet, until she grows up enough to demand more for herself, to be able to walk away from a codependant dynamic, and to grow healthier herself so that she is able to attract a healthier sort of partner, she is still 50% responsible for the kinds of situations she keeps finding herself in. Without realizing it, she's recreating the sort of dynamic that feels familiar.
Perhaps there are certain women who are afraid to admit they don't desire sex. But what is it about you that attracts them ... and what has twice attracted you to them?