I used to cruise a lot by myself. Once on board, I would go to the maire d' and ask to be seated at a table with other people traveling solo. Made some good friends that way.
I don't know if they still do this, or if it would be right for you, but I also used to book single share, where the cruise line matches you up with cabin mates of the same sex. Age ranges go from very young adults to retirees. And it gives you someone to talk to.
Whatever you decide, have fun!
P.S> To original question. When DH and I got serious about each other, I said I would not give up my cruises. Talked him into a 3 day cruise. A lot easier than convoncing him to try a week. He fell in love with it. No surprise there. Whatever "bribe" works in your marriage, go for it. Mine is too, um, personal, to post here!