Is a man's love for a married Christian woman—who will divorce her husband to marry him, with the possibility of her converting to Islam—considered a separation between spouses?

This relationship between you and the woman is forbidden, as it corrupts her against her husband and causes separation between them. This is one of the major prohibitions, for the Messenger of Allah, peace and blessings be upon him, said: "He who instigates a wife against her husband, or a slave against his master, is not from us." The fact that the woman and her husband are not Muslims does not permit corrupting her. Indeed, a man's striving to separate a woman from her husband is among the grave sins and an act of sorcerers and devils. You must repent to Allah and sever your relationship with that woman.