The dad's so hot but then i remembered he had an affair with that hag ew

I don't think so, she was probably his ex, bc theres a chapter revealing Jian isn't his son biologically and is the grandpas secretary's son.

She might have been, but iirc, when the dad had his happy little family and then the hag suddenly came out with his supposed son, he left Jitae's mom. So still, no