Re: second-wife
Umer - if I am ever allowed to have two husbands, you are my first choice 
Well, the peope involved are married already and have a life together (somewhat) already. The man has taken up the burden of two wives. Some would even say that is punishment enough 
. In my opinion, her family, if they truly cared for her, should support the choice she made. As sara pointed out, at least she is married as opposed to just having an affair.
No one wants something like this for their daughter, but the daughter made the choice freely. I would not want my daughter in a situation like this, but if she chose it and is happy, I would support her, no matter what I want or believe.
nia - he did commit to both of them and he is allowed to do it. I believe what you say totally, but these are young adults and have to live their own lives. They will learn in time, but since they are married already, it is a choice they have to live with and adjust to.