He fell in love with her during the two movies they did together. Many reports appeared in the media about their "love affair" but currently they are not seeing each other.
After the hero's family made serious warnings to the heroine, she started distancing herself from him. Although she still maintains good friendship with this rising hero who gave two hits in a row, she is now more concentrated on career. After she broke this off short-lived affair, her career is actually zooming.
On the other hand, this star is said to have become more sociable and mingling with other starlets. He used to be very shy and conscious of his not so good looks. But two big hits have changed perception about him and he is said to be freely interacting with his co-stars.
So this break up is a win-win situation for both hero and heroine.