Family instability creates a ghetto--that is, a situation in which children end up raising themselves, and quite often, trying to raise their parents as well. People who put their own immediate and selfish desires above the welfare of children end up harming society, whatever their intentions when they decide that traditional values about marriage and family do not apply to them.
You're confusing causation with correlation. One could just as easily claim that other factors associated with ghettos (poor economic wealth, high crime, etc.) create unstable families. Money problems can destroy a marriage very easily.
I'm just glad the Constitution keeps me from having to meet your particular standards for relationships. You are no different from the chicago aldermen that want to force restaurants to serve healthy food for the "common good". Nanny statists all.
P.S. I do "cohabitate" with about 60 other people (of mixed genders and races, no less) in a cooperative living arrangement. As little as 60 to 70 years ago, such an arrangement would have been (and actually was) considered scandalous and morally dissolute by the majority. Thankfully, we have more respect for the freedom of free association today.