It depends a lot on their individual personalities and somewhat on their upbringing too.
While Dev was always the more vocal one in their relationship abt love, haq and openly voiced his insecurities n jealously(Ritwick n even Neel case), Sona has always been able to control her emotions and hide her pain n jealously (Natasha).
Dev has lived in an environment whr he had to frequently prove and show his love to his family members again and again. If he misses a meal prepared by Ish or forgets to meet her or touch her feet before going to office, he has to quickly apologies to Ish abt it otherwise Ish will start worrying that Dev is going away frm her. If he doesn't take out time for Ish, she wud start questioning his love for her. Same goes with Neha...he had to continously pacify Neha and prove his love to her by showering her with material gifts. With Sona also, he wants to see her express it like he does to fully believe that she indeed loves him. He wants to see her love for him again n again. So even after she denies any relationship with Jatin, Dev's jealousy spring back and again need reassurance. He needs to know what Sona went thru in last 7yrs, to truly understand her words n actions.
In Sona's case, she had always lived a happy life with very understanding parents who never doubted her love n her commitment towards her family. So she doesn't hav d habit of giving assurance of her love again and again neither does she demand it from Dev. Many times she had said before that she doesnt knw how to do this typical romance. She understand Dev's insecurities frm Ritwick phase n understood its not abt Soha only. But the hurt is so deep, she cnt acknowledge openly tht Dev is jealous with Jatin bcoz of her not Soha.
Offcourse she wud be sad to know abt his GFs but to openly show her pain wud mean acknowledging the fact tht she still loves him n she can't let go off her facade.