everyone is guessing this that so lets guess and share your opinion what u feel
we have got one two flashback
its clear from flashback parul was married in rajvansh house that time kaushal was unmarried there was a daag on family meenu said she tried calling her husband she still wear sindoor
what i feel
parul is meenu elder brother wife and kunal is their son meenu brother done something grave and fled away or is in jail(meenu mention about daag thing) as parul was that time even having sindoor but later died thats why now no sindoor or maybe they will bring him back so to protect kunal who was in parul womb people may not trat kunal nicely thats why meenu adopted him and even snatched the identity from parul or she willingly gave away to protect heer son
meenu would have tolked to her husband for all this but he would have refused and thus they separated
i feel abir father would be nice person as abir cant be judging his dad that much or if he would have done some crime then he would be in jail
added to this i feel abir dad even has one of abir sibling most probably a younger sister and he is with her meenu would have loved abir alot and she would not have wanted to separate from abir thats why she gave away sister and took abir with her
i feel abir family would make dhansu entry when here rajvansh track will close or they will be in the condition to shift to rajvansh house
i even think that karishma mishti mother second marriage would be linked to abir familt probably married to his chachu i know the relation of mishbir would become complicated but not that much