but, if this was the case, then a guy like abhi wouldn't give up on his love. he would still love her. he wouldn't treat their relationship as a majboori.
so this means that they were always friends, perhaps from college days. slowly sheeka's side of the friendship became her love. and slowly pagalpan. of course, abhi, such a great friend promised to always remain by her side. but as veer sir said, that is different that remaining by somone for a lifetime.
as for the majboori, abhi said, "only my mom and I know what the secret is. and we've promised someone not to say the truth." ---that has to be sheeka's mom. she's the only one who can make them do such a thing. there are no characters left. obviously it's not veer sir, he even gave abhi the chance to change his decision. but sheeka's mom probably threatened to leave veer sir.