1) You keep acting like an interacial relationship means mutual exclusivity: that for me to be white and my wife to be black, one must intrinsically overpower the other. In a respectful adult relationship, this is not the case. So long as both sides enter the relationship with the potential to compromiose and adjust, they can overlap comfortably without friction.
2) It's a specious conceit that growing up in a household as you've mentioned will result in a positive character for the children, or community. I come from a single parent household, and ended up well, as did my brother. My wife grew up in a black household with both parents, and our backgrounds are compatable. Similarly, how many fucked up characters have come from two-parent, homogenous households? And how many positive characters have come from heterogenous or single-parent households? You wanna talk romance; I think you've got a pretty romantic view of how a household works. There are no guarantees.