All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Divorce is permissible in principle, but it could be dislikeable, forbidden, desirable or obligatory according to different situations.
In our view, you should not hasten to divorce this woman, rather you should take the matter easy especially that it was your parents who wanted you to marry her; it might be that Allaah will bless her for you if you desire to please your parents by marrying her.
Besides, you should know that marital life in not only based on love, there are many other great benefits which necessitate its continuity. There are many cases in which marriage was established on love but later led to divorce. It is confirmed that 'Umar said: 'Not all the homes [marriage between two people] are established on love; rather they are established on the basis of family lineage and religion [Islam].'
Therefore, love between spouses could occur after marriage even if initially there was no love between them. It could occur because of good relationship and living with the other spouse honourably. In addition to this, each spouse should devote himself wholeheartedly to fulfilling the will of the other.
So if you could keep her as your wife and get married with the second wife while being able to be just between them, then do so. However, if the matter is to the extent that you could not live with her honourably or fulfil her rights on you, then it is more appropriate to divorce her. Allaah says (which means): {But if they separate (by divorce), Allaah will provide abundance for every one of them from His Bounty. And Allaah is Ever All-Sufficient for His creatures' need, All-Wise.}[Quran 4:130]. However, we first advise you to make Istikhaara prayer before you do any of the above suggestions, and you should seek the advice of trustworthy Muslim brothers.
Allaah knows best.