Can You Say `I Love You’ while Fasting?
Question

My fiancé is Muslim. I have researched and learned the meaning and purpose of Ramadan. Please advise me on what is permitted, and not permitted regarding affection (holding hands, saying I love you, etc.) during this time of fasting.
Praise be to Allah.It is permissible for a fasting person to exchange affectionate and loving words with his wife (with whom he has done the marriage contract), and it is permissible for him to do some affectionate actions such as kissing his wife or hugging her or holding her hand, if he can control his desire. That is because `Aishah (may Allah be pleased with her) said: “The Messenger of Allah (peace and blessings of Allah be upon him) used to kiss (his wife) when he was fasting, and touch (his wife) when he was fasting, but he was the most able of you to control his desire.” (Narrated by Al-Bukhari, 1792 and Muslim, 1854)
Shaykh `Abd Al-`Aziz ibn Baz (may Allah have mercy on him) said:  
“A man may kiss his wife, joke with her and touch her without having intercourse when he is fasting. All of that is permissible and there is no sin in it, because the Prophet (peace and blessings of Allah be upon him) used to kiss (his wife) when he was fasting, and touch (his wife) when he was fasting. But if one fears that he may do that which Allah has forbidden because he is quickly aroused, it is disliked for him to do that. If he ejaculates , he has to refrain from eating and drinking for the rest of the day and make up for that day, but no expiation is required of him according to the majority of scholars. As for Madhiy (prostatic fluid) , that does not invalidate the fast according to the more correct of the two scholarly opinions, because the basic principle is that the fast remains valid and is not invalidated, and because it is difficult to guard against it. And Allah is the Source of strength.” (Fatawa Ash-Shaykh Ibn Baz, 4/202) 
This applies only to a man and his wife. As for a fiancée, before the marriage contract is done, the fiancé does not have the right to speak words of affection to his fiancée , or to hold her hand, because he is still a “stranger” (non-Mahram) to her and is like any other non-Mahram man.  No one should take this matter lightly, and it makes no difference if the fiancée is a Muslim or a Christian. 
We are happy to read your question about fasting among the Muslims, because it indicates that you have a love for knowledge and are keen to learn the rulings of this religion. We congratulate you for that and encourage you to learn more. We ask Allah to guide you to that which Allah loves and is pleased with, and we ask Him to create harmony between you and your fiancée, and to help you to marry him. 
And Allah knows best.