No one would have questioned Karishma if she would have not chant her BF name all the time. If her relationship was not working outside, she would have not rant his name. There r other girls in house, sambhavna, dimpy, mehak.. people would not know and would be least interested to know who is their BF unless they confessed so...no one really bothered about her closeness with Upen till the time this love angel came in picture...
I feel Gautam and Karishma both are wrong... but one point which gives gautam benefit over Karishma he never mingled with other girl atleast when his and D relation was on...
He got that opportunity when sonali kissed him in car when they both went out.. he could have used that opportunity...
but rather he questioned her in front of salmaan, d and all HMs...