I'd never be a brother husband nor would I ever want to have multiple wives. I'm not the romantic type and I'm not the super sensitive type, if I found a girl who was willing to accept me I wouldn't want to share her with another man!
Also having multiple wives is dangerous. The mores wives you have the less likely one of them won't be mad at you! ...well in reality I'd feel obligated to love each of them equally and seeing as I'm not some well of sensitivity to begin with that'd be nearly impossible.