1. Love Marriage (The term Arranged Love Marriage is more of a Fallacy)
2. If the marriage is all hunky-dory then would not happen else why not?
3. The ending is fine - Rishi & Ria gave all to the marriage but was not enough for their respective spouses - so they ended it, once they realized they could never fill the void in the hearts/minds of their spouses.
Dev & Maya always were on the brink of letting loose. They just needed an opportunity to break free, and nope no amount of love from their spouses would have saved them - finally they got what they wanted.
Yes story is far fetched but in times we are living in anything is possible
I am just glad that there was no kiss and make up and they did split for better or worse.