Dianne, my thoughts on this subject are going to be coming from the spiritual side of life. I believe in past lives and I believe it is possible to feel you know you love someone on first sight. If a couple was deeply in love in a past life and met in this life, then yes -- there can be love at first sight for the spirit knows and recognizes the loved one.
I would still caution to take it slowly though and do not jump into any commitments until you are sure of him and his true feelings. We are all on different levels of spiritual development and if he is on a lower level than you, he may not grasp the same feeling you are having, may not recognize your spirit. Past Love Reborn
If you do not believe in past lives then I probably have not been able to give you the answer you are seeking. We each have our own truths.
There is a thread in this forum on "Soul Mates" that might interest you. Have You Met Your Soul Mate?
Many people believe in past lives, many do not -- some like to make fun of those who do -- some who are at peace with themselves will just let others have the right to their own beliefs without throwing criticism or sm... a.. remarks out.
I wish you luck and all the best.