Well how do you think descendants are created? The bedroom and specific urges are a very important part of that. The sexuality of certain Royals also explains why they do not have descendants (think of Franz Duke of Bavaria and Jacobite pretender to the thrones of England, Scotland and Ireland). He and his male partner do attend events so it would be odd not to mention the person he shares his life with. Just like we do when Gustav prince of Sayn-Wittgenstein-Berleburg attends an event with his female partner.
With altered laws in most European countries we could see a younger generation of Royals actually marrying same sex partners if they choose to.
In time we will see how that affects successions and what solutions are accepted for those couples and potential offspring.
That all has little to do with sex but a lot to do with family and inheritance. It's a new chapter and so far unwritten but could become very intriguing in the next couple of decades.