While fasting, a Muslim is required to abstain from food, drink, and sexual desires and to avoid foul speech and haram (Arabic for: prohibited according to Islamic teaching) acts. In order to reap the great benefits of fasting, a Muslim is required to stay away from anything that may invalidate or even impair the reward of fasting.
Engaged couples, for example, should not involve in sensual talking that may lead to sexual excitement. Engagement is no more than a promise of marriage and, therefore, engaged couples are required to observe the ethics of dealing between people of the opposite sex when dealing or talking with each other.

Dr. Jamal Badawi, professor of religious studies and management at St. Mary’s University and the vice chairman of the Islamic American University stated: If this discharge is a result of some excitement that did not reach orgasm, it does not invalidate fasting. The same applies to men as well. If, however, the male discharge is ejaculation with the epic of sexual pleasure, it does break the fast. As to female discharge accompanied by orgasm, the majority of jurists are of the opinion that it invalidates fasting. The objective of fasting and the ground for immense reward of Allah is that we control our desires for food, drink, and sexual pleasure during the fasting hours, as specified by Hadith.
It is highly recommended to avoid situations that may lead to this sensation during the engagement period especially during the fasting hours in Ramadan. It should be added that the permissibility of talking with or contacting a fiancée is limited by ma`roof (Arabic for: legitimate discussion with the view of learning more about one another and plans for the future including wedding).