"How is it possible for one to love two (or more) people at the same time?". That's may be some people thought about polygamy. They doubt about the issue of polygamy in Islam. They believe the idea that God created one mate for each person, just as Adam had his Eve, and believe of true love or loyalty and love for one person.
"How can a husband love more than one wife while his heart has (or should have) room for only one?", some people claim of that. In fact, this claim may not be true, because when a parent, for example, has more than one child, does he or she love only the first child? The answer is "no." Parents do in fact love all of their children; so, such a parent does love the second child just as he or she loves the first one. Yes, a parent may love one of his or her children more than the others, but ultimately, this parent will always have a place in the heart for every one of his or her children.
In fact, if we look at the life of Prophet Muhammad (peace and blessings be upon him) as a role model, we will find that he married more than one wife and treated them justly; he loved them all.
Thus, if for any justifiable reasons a husband needs to have another wife, then he has to love both wives and treat them justly according to the teachings of Islam. But, if the first wife does not accept this polygamous marriage, then she has the right to seek divorce.
Below is an explanation from Sheikh Shaker Elsayed, a prominent Muslim scholar and imam at the Islamic Center, Washington D.C. about issue of polygamy in Islam :
The issue of polygamy needs explanation. I hope to help you understand it.
First, here are some facts about polygamy:
1. Polygamy existed well before Islam.
2. Islam did not start this institution.
3. It existed in all cultures, civilizations, and times.
4. Polygamy was unlimited and unconditional.
5. A man was able to marry and divorce at whim.
6. A man had all the rights and a woman had none.
7. There were no limitations on the number of women a man could marry at the same time.
Here is what Islam did:
1. Restricting this institution to a maximum of four women.
2. Setting conditions for justice and fairness of the process and of the relationship with these wives.
3. Instituting women's detailed rights that did not exist before in any culture, religion, or civilization.
4. Giving women the right of refusing to participate in a polygamous marriage by including this as a condition in the marriage contract.
5. Compelling men to wisely use the right of marrying up to four women and to use it only when there is a need.
There are circumstances that warrant polygamy as a matter of reality:
1. Existence of widows and orphans as a result of wars (which are still raging in many countries) or natural death, as mentioned in the beginning of Surat An-Nisaa' which reads, (And if ye fear that ye will not deal fairly by the orphans, marry of the women, who seem good to you, two or three or four; and if ye fear that ye cannot do justice (to so many) then one (only) or (the captives) that your right hands possess. Thus it is more likely that ye will not do injustice.) (An-Nisaa’ 4: 3)
2. Cases where a wife does not have as much desire for sexual activities as that of her husband, but they both still love each other and want to keep the marriage. It is better to keep the marriage than break it to establish a new one that may end up like the first one.
3. Cases where the couple have children, but they are also having problems in their life as a couple.
4. Cases of women who do not marry at a young-to-moderate age and do not normally attract young men who may prefer young women. These women may have the chance to marry married men and live happily with them.
Any woman who does not like her marriage has the Islamic right to seek divorce and get it, even if she does not have complaints of harm that support her claim. Under Islamic law, the mere fact that a woman does not want to be in a polygamous relationship is enough to secure divorce.
Reference : Islamonline.net