These are just my thoughts
To begin Aman's trust issues are because his dad left them for another woman who I believe was a courtesan so his distrust of Roshni whose mother was a dancer and the circumstances he saw Roshni . On top of it Salma' s behaviour didn't help.
So when Salma cleared his MU he was relieved and regretted his behaviour and he did make amends.
At this point I would like to ask why is nobody blaming or bashing Salma who was responsible to a large extent in creating a bad impression about Roshni.
When he saw Sameer hug Roshni he was angry and upset because at that point he was beginning to soften towards her. Like he gave her a new phone and waited for her to come down before going to receive Saima's sasural.
When Saima's SIL accused Roshni with evidence, this with the hug he saw and the money she withdrew and the fact his sister's wedding was in jeopardy plus the nonchalant manner Roshni answered and he asked her to leave but he was very sad about it.
Roshni acted so for Saima, Aman threw her out for Saima.
Where Aman went wrong was not even when he asked Alia and the baby to stay back but in his interaction with Alia.
And letting her stay despite her lies was his second mistake.
At this point Roshni should have put her foot down and given Aman an Ultimatum and said " Either she leaves or I leave" but she didn't do that but was trying to prove Alia's truth.
Many a time Roshni gets herself in sticky situation because of her over enthusiasm and to prove things.
Like during the baby kidnap scene she told Dadi she is going to the baby as he is alone and then went for her investigations and again why did she expose Chotu to Alia could have hidden him and he could have shown the video to Aman. I really think Roshni should stop flaunting her Ayaana sense too often.
Earlier Roshni before she realised her Ayaana power was far better.
In my opinion both of them are to blamed because they don't have proper conversation.
And we audience for asking extension and giving the CVs a great opportunity to kill a good show.