Makers have made both the characters full of errors ..... but Angad is a comedy of errors...as I said once before the matter is not about Seerat's behaviour....she is bad ...there will be many other girls in future....who can do this.....the issue is Angad...
Sahiba gave him numerous chances....he defended candle light dinner, he said u can't explain truth to someone in a way where they think ur giving them poison, even before MU seerat touches him to check his shirt tag and make him try shirt.....he even refused to come clean at hospital and later when she is upset foe ILU he says "gal khatam" and walks off. She asks him even then is there anything else I should know....but his ego does not allow him yo say it.
Both are egoistic but this mess is created by Angad's ego...and STUPIDITY. Sahiba thinks he is cheating.
When Inder cheated, did Manveer fight with Gayatti? No, she fought with her husband. Sahiba knows how her sister is, she is not disappointed eith her as she had no expectations from Seerat....she is hurt and dissapointed with Angad....hence she is upset with him.
The only reason she is not giving reason to family is - I think to save Angad embarrassment....she may be like when my relationship has no value ... why create a scene. Best thing is to move away....and she did that.
She climbed down a curtain for him. Angad was responsible for her shop burn and risked his life for her. Sahiba was responsible for Simar mess so risked hee life foe redemption...again Sahiba was responsible for Rumi so risked her life to try to save Angad....
We will keep going I circles here looks like.