IF it is not about sex, than for what reason does a man need multiple wives, except to satisfy his lusty desires. Marriage is supposed to be all about Love, if it is all about sex, than it wont last. I married my wife because I love her and still do, that wont change, getting another wife wont make me stop loving her, but i will more than likely love the other less, and she will always be second, actually third if you add Christ into the mix, and I am not willing top put any women through that.
What was it JEsus said
Luk_16:13 No servant can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.