Your son and daughter together

Meilsa is sitting at the edge of her bed. Next her Rowol, her half-brother is sitting there as well. And they are kissing each other.
“Umm, Meilsa.” Rowol moans. “I love you so much.”
“Mmm, Rowol.” Meilsa moans back. “I love you too.”
By the ****. Your children are actually in love with each other? How long has this been going on? Do they always kiss when they are left alone? Then you see Rowol place his hand on Meilsa’s thigh, Meilsa doesn’t stop him and against your wishes, you are getting hard watching them.
This is wrong, you should stop them. But then again, they look like they both want it. What will they think of you if you deny them their love?