No problems with a harem!?

"...no problems even if you make a harem."

"I have no problem either," Lucy added from the side.

The reason both of them were so chill about Lith having a harem was, firstly, they had no interest in a person of the opposite gender and Lith was the only one for them. Secondly, they had faith in Lith. They believed that he would always love them more than he would love anyone else, just like how they loved him.

"What!? Are both of you out of your mind? No problem with a harem!? And wait, why are you encouraging me to make a harem in the first place!?" Lith asked in shock.

Were his mother and sister okay in the head? He thought to himself. Who in their right mind would suggest such a thing to the person they love?

Weren't women supposed to be dramatic, possessive and jealous if another partner was involved? Wasn't sharing a thing loathed by everyone? Why are these two acting like it's just a casual thing?