A lot of this depends on you. What if he were to say the same thing about you? If, on your wedding day, your fiancé had as little for you as you feel for this fellow, would you be crushed? Have you found yourself to be someone who warms up slowly and only develops chemistry with others over time, or does your past indicate that this is a “we have it or we don’t” proposition? What if “chemistry” is something you aren’t going to feel for a mere mortal again? What if your past idea of chemistry, after you think about it, was not attraction to something good but attraction to something thrilling, to a glamour that does not bode well for a lasting marriage? Did you ignore a lack of chemistry in the past, only to find you were ignoring your intuition about the match? There are innocent reasons that some people marry the exact wrong person, but it is good not to make the same mistake over and over or to rush from one mistake into the ditch on the opposite side of the road.
You are looking for the man you will give the rest of your life to. You don’t have to like everything about him, but he deserves to have your affection without reservation. That is your affection, though. For some of us, that includes immediate “chemistry.” For some of us, it is something that develops. For some of us, it is more intellectual admiration than automatic emotional infatuation. Some of us want our marriages to be mutual fidelity societies, others want a mutual admiration society, and others feel a need to have a mutual infatuation society. Where are you on that continuum? Where is the guy you are dating? Have you asked him? Do you have differences that you can both accommodate?
While I would not say that it the fires of infatuation are necessary for a good marriage–Heaven forbid!–I also caution you not to give too little weight to the consolation of natural attraction, either. Open your eyes about what you are choosing and be able to admit what you are choosing.
Again–have you talked to him about this? I don’t think it is right to conceal this from him. I wouldn’t say, “Hey, I have no chemistry with you. Is that going to be a problem?” I think I’d explore the entire subject of “chemistry” with him, including how your present experience compares with your past experiences (which admittedly did not lead to a valid attempt at marriage) and what his experiences have been and how they worked out.