The singer is afraid over the money Fielder-Civil will get from her estimated 10 million pounds fortune.
The latest twist in the couple's 18-month marriage came just hours after Fielder-Civil asked Winehouse to pay his 30,000 pounds rehab fees.
And after he said: "I am gonna see my wife and take her knickers down."
Winehouse now refuses to see him while he is in rehab at the Life Works centre in Woking, Surrey.
"The family saw a solicitor this week. Amy fears Blake's just after her money," News of the World quoted a source, as saying.
"Amy woke up and smelt the roses when Blake tried to get her to pay the 30,000 pounds rehab bill.
"Lawyers said Blake stands little chance of getting a huge pay-out.
"For the first time ever Amy has her mind on the notion of divorce. All her family and friends are delighted," the source added.