Schiller DuCanto & Fleck, which bills itself as the largest family law firm in the country, celebrated its 40th anniversary last week.“It’s unbelievable 40 years have passed since Joe DuCanto and I decided to start this firm,” said Donald C. Schiller, who still serves as chairman of the firm. “We dreamed of becoming a large firm, but we never thought we would be this big.” Schiller and DuCanto joined forces in 1981 after working the opposite sides of a big case.“We were both very busy at the time and had thought we …