Huge cruise fan here. If you have not checked this out on cruisecritic.com there is a LGBT forum. You could either look for someone to plan a cruise with or just read about people's experiences.
We went on a Royal Caribbean cruise in August (my 7th) and I had a blast. In large part because I found the "roll call" on cruisecritic.com for my particular sailing and thus had made a bunch of friends before even setting sail. Two people in our group planned shore excursions having done a lot of homework in advance and invited others to join them. We had two great days and I have some new friends on Facebook to share memories with!