i saw your question about being confused on do you still like me so i tried to reply there but unable to do so ... so i am replying here
i see a lot of readers confused over the plot so i will be putting down all the important points under my comment in the comment section on the top which might help readers in clearing their confusion & you will get the answer to your question


I actually forgot about all those family thing about Glunn
so when he said his parent really do loves each other, but his father fell sick, does it means that his father decided to NOT marry the one who can withstand their blood and choose Glunn’s mother instead?
That’s why Glunn is looking for the choose one, to avoid being sick like the father?
I think it was that when the couple produces a child the father falls sick and dies due to the curse
I understood that Glunn's mother was the spouse chosen by the dragón and they loved each other. But despite of that the father will still get sick
so what’s the use of it?