So yes, he shouldn't have said what he did but I don't think it's that out of character for a young person who is newly in love. Jealous happens and so does insecurity. There are times when Simi will need that reassurance and times when Abhi....that's the point of their friendship turned into relatinoship.
For now, i'm eagerly waiting for this making up session (the only fun part about them fighting is watching them make up!).