Is it permissible to marry another woman if there is a strong possibility of divorcing the first wife?

You are permitted to marry your maternal uncle's daughter if you are able to treat her and your first wife justly. However, if doing so would lead to the separation from your first wife, then the advice is to live with your wife with kindness and be patient with her, and to divert your heart from attachment to your maternal uncle's daughter by seeking Allah's help and striving against your own desires.