Assalaamu alaikum,
(gently) I understand your feelings. If you are sure that this is what you have (if this has been confirmed by a doctor), I personally don't see why you would need to discuss this before marriage. From what I have read, this is not at all harmful or problematic in any way. They are just cosmetically a natural variant.
However, I think that I would prepare some information for your spouse, in case she has any questions or concerns. Perhaps even a doctor's certificate, just in case. (smile) But perhaps you may not even need these, at least not at first. Remember, she will very likely be just as nervous as you on her marriage night (perhaps more... she may have heard that sex hurts-especially the first time). If you focus on calming her nervousness, this will likely help you to forget your own.
May Allah, the Fashioner of forms, Bless you and your future wife with a caring and fruitful marriage.
