Engaged but no wedding date

I have been engaged for approximately one year to a man with ADHD. We have been in a relationship for three years. At first I did not notice his symptoms; I thought he was just very energetic and spontaneous. After knowing him for three years now, I am beginning to realize that these qualities are not going to change. He is extremely messy and rarely helps with chores. He had a gambling problem which stopped, however I am always afraid that it will return. He is been pulled over numerous times for speeding and had his license revoked. He also seems to be addicted to pornography. I cannot explain why I am with this man. He's charming and adorable. I am extremely afraid to get married. I'm afraid that our children have ADHD or autism. I imagine that our lives will be great together. I keep focusing on the positive things, like how he stopped gambling. Sometimes I do feel more like his mother than his fiancé. I love his spontaneity and enthusiasm for life, however I wonder if it is compatible with the type of life that I envision. I feel very alone and cannot really describe these feelings with my family members. I have a counselor, but feel so guilty having these thoughts. At the moment, we live in separate states so it is very hard for me to assess how our relationship will be once we live together. I am at a loss and I'm really struggling with my decision to get married. Most of the time I'm very optimistic. But every so often I have a day where become very scared, terrified. I read people's comments on this forum and can relate tremendously. I feel like my brain is telling me to run. My heart is telling me to hold on. I have never been so conflicted. Fortunately, we have not made any definitive wedding plans yet. However we will not be together for at least a year and it is very difficult for me to assess our relationship apart. I am really struggling and could use some advice. Thanks.