So hear me out before throwing chappals at me 😆
Anuj said, "Ek rishta aur tha jahan mujhe bolna chahiye tha lekin maine wahan bhi kehne main der karhi dali" .
So idk it makes me wonder did he have a kid from one of his ex girlfriends, and for some reason the ex-girlfriend didn't want him to be involved in raising her. In USA, if the mother doesn't let the kid be in touch with the father for whatever reason, the law mostly supports it. The single mother most of the time gets full custody too. He might have had visiting rights when she was a kid but as the kid grew older maybe they drifted apart because his ex-gf didn't let him be a part of the daughter's life. As the daughter turned adult, she might not have wanted to keep in touch with Anuj for whatever reason and she would have every right to.. Maybe he doesn't know about her whereabouts hence he hasn't told Anu about her at all. Just a thought 😆
Whoever this person is has to be someone important in Anuj's life. I don't think it can be a far relative, an adopted sister or a cousin because they wouldn't have hold that much importance in his life. This person seems to be important to Anuj and for some reason they have strained relationship. Per og, its some far away related cousin sister.. but here it wouldn't make sense for it to be a cousin sister... It would either be his real sister or his daughter lol.
Ex theory is out of the window as we have witnessed Anuj's deep love for Anu. He wouldn't care about an ex where he should have expressed his feelings cuz he never loved anyone romantically other than Anu.