It may not be just the doubting her of affair but prolonged mental and physical abuse from 8-9 months plus pressure of medical studies and assignements. Every week she is abused due to one or other thing. Don't get me wrong but in real life even the most educated and urban women are drove to suicide because of depression due to abuse. Just because no TV serial shows FL doing does not mean it does not happens. So I see suicide attempt due to this reason.
I get your point but why it is necessary to normalize the sensitive topic like suicide for drama. There was so much good and positive vibes and this sudden shift to the storyline, Virat's nonsense outburst and Sai's pathetic step towards killing herself is not justifying the point of this track at all. This track was added in KD because at that time KD had a little less ratings so to spice it up makers brought this track but in Ghum it is completely unnecessary at this point because the ratings are very high and also Virat has been shown as a supporting husband throughout the week but now his sudden shift in character from a lovely husband to an ahole is horrible. Why everything had to be copied from KD that is my point.
Bollywood
Mahabharat Katha
4