I can't help but notice the devdas track whereby they've replaced the alcohol with the reckless behaviour and fights.
I think this is the way the CV's are taking the track and with Shilpa here she will become his Chandramukhi, someone who will help him come back to life.
And as for Riddhima being jealous or not liking Shilpa i think that's just a temporary situation same as when Paro was unsure of Chandramukhi to begin with (remember the Ash/Madhuri scene before the Dola re Dola song)
Once she realises what kind of person Shilpa is she'll be happy and let her be with Armaan.