Whats the big deal about 8 years. Laila to me is nothing but what she is now. Rudra was with her for 8 years and she couldn't persuade him to marry her or love her in these 8 years . What a waste of time. She was happy to be his mistress.
During haldi scene laila saw a side of Rudra which she has never seen. Laila's presence didn't bring out this side of Rudra in these 8 years.
Paro was with him for couple of weeks. Now Rudra lost complete control over himself. He is getting restless .But he can't loose. He thinks he will not fall for any one until he met Paro.
So, please don't even compare Paro to Laila. One is fighter and other is a looser.