Praise be to Allah.
There is nothing wrong with a man playing with his wife, or a wife with her husband, by saying words while fasting, on the condition that there is no danger of either of them climaxing. If there is the danger that they may reach climax, as in the case of one who has strong desires and who fears that if he plays with his wife his fast may be broken by his ejaculating, then it is not permissible for him to do that, because he is exposing his fast to the risk of being broken. The same applies if he fears that he may emit prostatic fluid (madhiy). (al-Sharh al-Mumti’, 6/390).
The evidence that it is permissible to kiss and play with one’s wife, if one is sure that there is no risk of reaching climax, is the report narrated by al-Bukhaari (1927) and Muslim (1106) from ‘Aa’ishah (may Allaah be pleased with her) who said: “The Prophet (peace and blessings of Allaah be upon him) used to kiss and touch (his wives) while he was fasting, and he was the most in control of his desires.’” In Saheeh Muslim (1108) it is narrated from ‘Amr ibn Salamah that he asked the Messenger of Allaah (peace and blessings of Allaah be upon him), “Can a fasting person kiss (his wife)?” The Messenger of Allaah (peace and blessings of Allaah be upon him) said, “Ask her” – meaning Umm Salamah – and she told him that the Messenger of Allaah (peace and blessings of Allaah be upon him) used to do that.
Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) said: “With regard to things other than kissing that may lead to intercourse, such as embracing and the like, we say that the ruling on them is the same as the ruling on kissing, and there is no difference between them.” (al-Sharh al-Mumti’, 6/434).
Based on the above, your simply saying to your husband, “I love you,” or his saying that to you, does not affect your fast. And Allaah knows best.