If you really support him and like him then let him live his life as he wish without complaining. It's not like you are gona get together with him. You won't loose anything. He will be happier in general with that person, get more inspirational, write better songs for y'all! Isn't that what you want? Don't you want that cute face to keep smiling? Cmn, grow up and stop being so dramatic for their relationships with other people! What if every partner you have became hated from everyone and giving you shit comments on your personal life, that would suck wouldn't it? Just be happy that he found someone he likes just like everyone should be when someone finds love.
It's funny because there're rumours that say that they're both homossexual, so it's probably just a stunt to hide their sexuality. Plus, they're not the only ones on the yacht. Ellen Degeneres and her wife are there as well, and they're both gay as well. Interesting, right?
To be quite truthful I cannot understand why you are so obsessed with this.. Him & Her don't interest me in the slightest.. There are far more important things in the world to be concerned about rather than these two individuals.