After ending a long relationship, I think going the cruise route is a sound idea. Meeting people onboard is easy if you are the least bit outgoing. There are endless opportunities, for easy conversation, especially at diinner, so if you find yourself the first night at a table you find not to your liking, ask the maitre'd if there are any singles that they could seat you with.
Check the dailies for any singles activities, and join right in. Have fun, and mingle, mingle, mingle