Now that Shiv's chosen Gauri over Ips (for whatever reason), his 'past' shouldn't make a difference to Gauri. In other words, if the relationship bt shiv and Ips does come out now, it won't be any great shakes as Ips is now married and out of shiv's life.
It would have been another story if Ips hadn't got married.
Of course, if the two go back to where they left off, it's different. But as it stands, there's no reason for Gauri to be upset over shiv's past...for that's what Ips has become now.