Amy Winehouse’s wild week - including an alleged assault and subsequent arrest - was reportedly sparked by her telling husband Blake Fielder-Civil that their marriage is over and she’s already got a new man.

According to the Sun, Amy told Blake the news during a visit to HMP Pentonville on Monday afternoon and afterwards, began what would become a two day long party.

A source told the newspaper: “She has been fed up for ages and saying she wants to call it a day.”

“All Blake does is scream and shout at her on the phone from prison and curse at her and his family blame her and criticise her. The pressure has been building and building and while she was away working with Mark Ronson she had time to think about everything.”

“[Blake’s] trial is coming up and as it gets nearer and nearer the thought that he could come out has been on her mind - and it’s not what she wants any more.”

“Even the thought of having to go to court and publicly support him and see his family has been too much for her and has been doing her head in.”

“She has been turning up late and missing visits so she decided to just be straight with him. He burst into tears and was begging her. But once Amy has made up her mind, that’s it.”

“While he has been inside she has not been faithful to him and got herself in a position where he couldn’t come back anyway because too much has gone on while he has been inside.”

“She is filing for separation and making it official and has been celebrating ever since.”

The source added that the biggest celebration has revolved around outting her relationship with her manager’s assistant, Alex Haines. She was photographed with him while out in Camden on Thursday night but the source claims their affair is already a month old: “It is a relief that it’s finally out and they have everyone’s 100 per cent backing.”

“Alex is a good boy. He doesn’t smoke or take drugs. He isn’t a big drinker. Amy has really fallen for him.”

“Amy hangs on his every word. He is tough and Blake is scared of him. That has made her feel ready to end it.”

“[But she] doesn’t want the truth coming out because she doesn’t want [Blake] reading things that will upset him in case he tries to do anything silly in jail.”

“She does care about him still and has been trying to be seen to support him through his jail ordeal - but she just doesn’t want to be with him any more.”