All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
You are definitely not allowed to mix with a marriageable man or socialize with him. It is apparent from your question that you are too open with him to the extent of allowing him to kiss you and enjoy you which is a great sin. The honor and chastity of a Muslim woman are the most precious matters she owns in this life. For more details, please read Fataawa 86729 and 82730.
A disbeliever hates Allaah, His Commands and His Prophet. So, a person who loves Allaah, His Commands and His Prophet should not have any affection towards him, as we mentioned in our Fatwa 88293.
Know that the gate to repentance is opened wide for every person as long as he/she does not face the agony of death. So, you have to sincerely repent from this sin immediately. To know how to repent please refer to Fataawa 81467 and 83904.
On the other hand, you do not have to reveal your past sins to your future husband as we made clear in Fatwa 86058.
Allaah Knows best.