once he knows the truth about arvi, he will support ovi because somewhere deep down even we arvians know that arvi were wrong in hiding the relation and handling it.
instead of telling everything to archu about the phone call she went on to look for the unknown caller so that she can shut that person's mouth and arjun instead of waiting for "DK-the tourist baba" should have opened his mouth and told the truth to ovi. so overall arvi are playing with the emotions of arman who trusted them the most. and if after that manav supports ovi then its a natural reaction from a father and a person whose trust is being broken.
overall arvi gave everyone a chance to point fingers at them, and even we arvians know it - arjun lied but purvi supported him. loving each other is not a mistake but hiding that love on the base of someone else's trust <arman> and hopes <ovi> is wrong.
i am arvi fan and will always love them but their way of handling this whole thing is wrong or we can say the way cv's made arvi behave is wrong