I do not think Anuj is that bad as Tulika. Anuj truly loves Anu and he cares for her and her future. He is so protective that he thinks that Anu can not fall in love with a married man. He does not want her life to get ruined. Nothing wrong with that.
He would be okay if Anu didn't confess her love for Nikhil. He would be okay if Anu didn't love him or anyone else. It's bothers him that She loves someone and is a married man.
Wouldn't you get jealous if you love someone but she/he loves someone else? I would. No doubt on that. Anuj is not a lead charactor, that's why his love is not acceptable. Why?