I think I can confuse those to some degree. The laws get their legitimacy by the public consent which is primarily based on the customs. When in Rome, do as the Romans do.
Nice question, but I'm not the one who could properly answer that since I haven't fought those wars. The only thing I could say on the case is that in a typical Western country a male has no legal limit on how manystable sexual contactsmeaningful relationships he could have and how many children would be born as a result. The male would have financial obligations to support all of those children and their mothers, despite the fact that legally the male and those females are as close as the "separated couple". Speaking of which. If a man is married three times and have kids with all his divorced wifes, he is legally obliged to support all of them. Both cases are a de-facto polygamy acceptable (and rather widely spread) in the Western countries. If you're interested, I could give my opinion on the monogamy (which I like), but that would be another discussion, I guess..