After watching today's episode, I think it is pretty clear that the marriage is in fact, real.
Considering the fact that the show is about Mohan and Megha, they have to eventually find a way to get him out of this marriage. That would mean either they get a divorce, Riddhima dies or they annul the marriage. None of these routes will turn back time and unfortunately, Megha will now become Mohan's second wife.
I can't speak for anyone else but according to me this show is no longer what it used to be. The CVs could have turned to plenty of other tracks to keep the show going without compromising the integrity of the show. For example, what has stunned me over the last few weeks is the whole Megha-Amar relationship. Why has she not spoke to his picture in ages?? I think they need to reconcile Megha's feelings and they've totally missed that. There have ignored this opportunity for character development.
I don't want to deny them of credit though. Kunal and Akanksha were brilliant throughout the episode. We felt their love and Mohan's pain. Very well acted episode. And Mohan is right. Marriage is not a joke. Regardless of what we think of Riddhima, he did marry her. So now he must fulfil his duty as a husband.
I have no idea what the CVs will do now. But sometimes I wish they would just read this forum before they come up with their brilliant ideas.