My partner and I were on the Silver Cloud last year for a 16 day cruise in the Mediterranean. I am 43 and my partner of 23 years is 41. I must say that we were relative "youngsters" on this cruise. We met many nice people that were gay friendly....but no other gay cruisers. The most fun we had with other gay people were the staff and entertainment people. The fitness instructor, Stanley, was very cute and entertaining.
The fact that most folks on this cruise were quite sophisticated, and therefore gay friendly, made it pleasant. We met some very nice people with which we enjoyed our excursions and activities with.
If you like, I can give you some insight into the Silversea experience. Brian and I are going on a Radisson Mariner cruise in a week.