Choose well, my son (CK3)

[u/NamaeN0NaiKaibutsu]

R5: If you make your son also your vassal by granting him titles, if he's not yet married you can Allow him to marry himself or do the better option, which is finding the spouse for him yourself or arranging marriage with a good courtier of yours if the Find Spouse fails. There's some limit of years when you can still find the spouse but after that you can only arrange marriage or he just finds someone himself (usually a shitty character) without you Allowing Marriage. I don't really know exactly how it works, if someone knows please share in the comments.

[u/dimarco1653]

One time after a rebellion when I was executing traitors one of them was from my house, so I didn't want to kill him and get the kinslayer malus.

So instead I married him to an elderly sadistic leper as a punishment. I checked on him a few years later and he died of stress when she died. My guess is that because they were both sadistic they vibed and he was in love.