I agree with most of what you said, Henry. However, we depart when you theorize that black men are leaving black women, for other races, because of their promiscuity. I don't think this is true. In fact, I believe that the black woman, as a general rule, has yet risen to the level of white female promiscuity. It has not been that long ago that one of the primary reasons that a brother wanted white women is because of the stereotype of them being more promiscuous and willing to do certain things that black women would not do. However, I will say that black women have seemingly been doing a lot of catching up in the last 20 years.
I think that the rise of black men dating other races of women is linked to the need of the male to feel dominant in the relationship and black women are not so easily dominated relative to other races. Of course, this is not an absolute rule, but the general rule of rise in inter-racial relations. Now, I do believe that it is the role of the man to be dominant in the relationship, as generally few women will respect a man she can dominate. Women like men who take charge, but that is not a license to abuse. Thus, instead of becoming stronger and sticking with the black women, many brothers simply choose to date races of women he perceives as weaker, so he can dominate without having to become stronger.
What many brother don't realize is that much of the attitude of the black women is simply a sheild for protection. That sheild can and is often lowered once a brother proves himself worthy of following and dominance.