If what I believe is right, Sultan will be around for a longer stint in Madhu's life but any kind of romantic feelings will be only on Sultan's end, if any. I remember him saying his wife's betrayal has made him distrust everyone, so him too falling for Madhu so soon is highly unlikely.
Madhu loves RK and nothing is going to change that. I know the Aryan angle makes us uncomfortable but I won't start predicting things until CV's show something concrete on the Sulbala angle. What I'll looking out for is Radhaji's angle as what she thinks/speaks will shed some light on the future track ... till now she's been hopeful, but she seemed very disturbed yesterday. If she gives up, then Sulbala will be a surety, IMO.
I'm watching it for Rishbala and Madhubala means RIshbala for me ... if this equation changes, I will take ST's advice and call it quits with this show.