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.
First of all, it should be noted that you and that girl did well since you stopped meeting each other and started to be steadfast on the correct path. We ask Allaah to enable you more to do good. You have to know that there are some conditions that should be met for the marriage contract to be valid, the most important of which is the consent of the guardian and two witnesses. It also has two pillars, which are proposing and accepting [of the proposal]. If the marriage contract took place with these conditions and pillars, then it is a valid marriage and there is no consideration for claiming not to be content in one's heart. So if the marriage took place as mentioned then this woman became your wife. Therefore, we advise you to continue your marital life with her and not take into consideration any thoughts which may hinder you from this. It might be that Allaah will bless your marriage to her and make her a comfort to your eye and bless you with pious children, especially that you intended to please your parents by marrying her. Allaah Says (what means): {…perhaps you may dislike a thing and Allaah makes therein much good.}[Quran 4:19]. Furthermore, the Prophet said: "The pleasure of Allaah is attained by pleasing parents." [At-Tirmithi] It should be noted that you are not obliged to keep her as a wife, and divorcing her is not considered as being undutiful to your parents if one of you is harmed by this marriage, but we advise you to keep her and live with her honourably. Not all homes are built on love, as the saying goes. May Allaah take out from your heart the hatred you have towards her, as the hearts are in the hands of Allaah.
As regards the other girl, you may marry her after divorcing your present wife, or marry her as a second wife if you are able to be just between them, because being just between them is a condition for polygamy and you should fulfil their rights, Allaah Says (what means): {But if you fear that you will not be just, then [marry only] one….}[Quran 4:3]. If it is not possible to marry her, then you should not think about her; it might be that it is evil which was driven off you by you marrying the other girl, Allaah Says (what means): {… and it may be that you dislike a thing which is good for you and that you like a thing which is bad for you. Allaah knows but you do not know.}[Quran 2:216].
Finally, it should be noted that residing in a non-Muslim country has many disadvantages on a Muslim's religion, so it is not permissible to reside there except for a necessity or a dire need, like for the purpose of treatment, calling to Allaah and the like. For more benefit, please refer to Fatwa 86405.
Allaah Knows best.