I have been to Bermuda on the Meridian, Horizon and Zenith from New York, Philly and Charleston more times than I can count, and October is by far my favorite time of the year to go. Yes, the seas in the Atlantic are rougher than in the Caribbean and I have seen some seasickness occur among passengers. But AR's comments were right on about hurricanes and about seasickness medications. Though I rarely need it any more, I am a firm believer in Bonine (meclazine) as a preventive measure. However, I am told that it will not work if you are already sick. It does tend to make you slightly drowsy but not nearly as much as some of the other motion sickness meds. I just returned from a cruise with two friends who were also afraid of seasickness and I had them take one-half tablet about 30 minutes before we sailed and periodically through the next day at sea, and they did not experience any nausea at all. After the second day, they stopped it altogether and were fine for the rest of the cruise. However, we were in the Caribbean and the seas were relatively calm. So I urge you and your wife to take it as a preventive medication until you get your sea legs.
I know you will love Bermuda. It remains my favorite island and my favorite cruise.
All the best,