Because I don't know much about this topic, I only want to give my opinion about having the 2nd marriage.
First of all, in many countries (including Indonesia) it's considered normal to mary first before you get the package we westerners mostly get in a much earlier stadium. Having a household together and sex for example. So marriage does have a different meaning over there, compared to us.
In spite of that, I think monogamy is a myth. Isn't it against human nature, to have only one partner in life? Even in civilisations, muslims for instance, it's proven that monogamy does not work in many cases. Not only due to the fact that men's (and I suppose women too) are naturally programmed to have more than 1 sexpartner in a life, but people mostly tend to change. And if your husband or wife chooses directions in life you cannot follow, you should have the freedom to end it. And choose another one.
So to answer your first question; yes, I think polygamy is good.