I think, that since both of them aren't getting married for themselves but for the sake of their children, they don't feel the need to meet or converse like the way it's usually done. I mean we saw in yesterday's episode that Yash and Arpita had the whole meeting each other before the wedding was arranged, and Yash actually officially proposed to her at the end. At that time he was excited, happy and eager at the prospect of getting married, but things are extremely different here.
Both Yash and Aarti have absolutely no interest in getting married again, but the constant pressure from their families, and the growing needs of their children have forced them to swallow this bitter pill and accept the proposal. It's kinda like the scenario where you know that no matter how much you run away from something, it will never stop harassing you, so you might as well just give in even if your heart isn't in it, just so the nagging can stop. Emotions aren't invested, neither can actually build up the courage to actually look at the picture of each other because the thought of remarriage is still a foreign one, something they have yet to accept completely. They're both going on a limb here, trying to trust their parents to make the right decision, because their heart just isn't in it.
But you're right, they do need to at least meet up once, even if it to just discuss their children, but I think both are avoiding it, because once they meet, it will become official that they really, truly are getting married. I have a feeling, or at least I hope that that once everything is set and confirmed, they will meet each other. It might be ridiculously formal and awkward, but it needs to be done. And in Promo #2, the one of their wedding night, they both seem to be kind of comfortable talking to each other and that won't happen unless they've already interacted once of twice before!