Exactly! Manbeer's feelings are justified. Maybe this is why she is so bitter. My guess is that eventually she is going to break down and we will get to know that behind her tough exterior was her true feelings and hence she is so protective of Angad and wants him and his life to be perfect. Eventually will soften towards Sahiba and accept Simran. As all itv females unless they are outright vamps are Mahaan and ultimately will forgive their husband's illegitimate extra marital affair and accept their illegitimate children. In some cases the female character is labeled to unreasonable if they don't accept the child and they are always emotionally blackmailed by circumstances or family members to accept and raise the child. As Varsha did in YRKKH, Sunaina did in Ek Rishta Sanjedhari Ka, Tanya and Veena did in Kahaan Hum Kahaan Tum, Kokila did in Saath Nibhana Saathiya
Ofcourse the kid is not at fault but they way they act like the wife who was cheated on is being unreasonable and has to accept the child as that's what a woman and a mother does... the way it is chosen is kinda problematic imo. Plus in most the show (examples above they eventually accept and forgive their husband's as well)
I think as Manbeer isn't the vamp she will accept Simran and her character would then soften up.