From GameWatcher: “Paradox has confirmed that same-sex concubine mods are returning to Crusader Kings 3. On a similar note, same-sex marriage mods are also on the way, although they’ll take a while longer to arrive.

While same-sex relationships were a part of Crusader Kings 3 since launch, players had to resort to using mods if they wanted a playthrough that allowed same-sex concubines. Last month’s Corvus Update 1.3 broke these mods, but the publisher has been aware of the issue and is working on a fix.”

Source: N4G PC Crusader Kings 3 Enabling Same-Sex Marriage Mods by Patch 1.4, "if everything goes as planned"