When Naga Chaitanya could have ended with Shruti Haasan:

Between 2010 and 2014, Naga Chaitanya and Samantha  were good friends. It was also during that time, when Chaitanya dated Shruti Haasan. They were introduced by their friends and became inseparable. There even came a time when rumors about the two getting married started going around.

However, after a few months, both of them separated and went different ways. (Thankfully)

And how Samantha could have gotten together with Sidharth:

During the same time interval from 2010 to 2014, Samantha went out with co-star Sidharth. Both of them acted in the movie Jabardasth. The whole world knew about their relationship, but the two did not confirm anything.

But things went wrong and Samantha broke off their relationship in 2015.