No, but depending on the itinerary, you will definitely find a lot of other LGBT folks. On the WBPC last April, all 4 of our table mates were gay and there were lots of other queer folks on the cruise. On the flip side, we found that a Thanksgiving Eastbound Caribbean cruise we did on the Fantasy was very family-oriented and we only met one other gay couple.
I would recommend joining your cruise's Facebook group or Disboards meet-up group and try arranging something.
There’s no advertised “Friends of Dorothy” like on other cruise lines. However, hang around the adult-only areas and activities and you’ll almost certainly meet some people. We’ve also found that two adults of the same sex in a stateroom tend to get paired with others for dinner table assignments.
Join either the dis boards thread for your cruise or the fb group and ask if there is a group meetup or you can organize it yourself. We have been on 14 Disney cruises and have either joined a existing group or we started one on every cruise. On the EB Transatlantic in 2017 there were over 40 at the meetup the second day of the cruise. Good luck!