Second thoughts? Russell Brand regrets ending his marriage to Katy Perry, according to new reports - He reportedly sent his ex-wife an email saying ending their marriage was the "biggest mistake of his life".

They say that the grass is always greener on the other side, and this is something Russell Brand may be currently experiencing.

The British-born comedian is said to “seething with jealously” over Katy Perry’s new romance with Robert Ackroyd, of the band Florence And The Machine.

So, jealous, in fact, that  he allegedly sent the songstress a long email admitting that he “gave up” on their marriage too soon.

A source close to the 36-year-old told Grazia, “Word has it Russell was “seething with jealousy” when he saw pictures of her with Rob. He apparently feels he gave up on their relationship too easily.”
The source continued, “It’s fair to say that Russell only wishes Katy happiness but perhaps he should have realised just how special his wife was when he was married to her rather than five months later.”

Russell filed for divorce from Katy in December and it was finalized in February.

Here is a clip from the Saturday night incident in Atlantic City.

[yframe url='http://www.youtube.com/watch?v=dxVe9Rqk0mY']