Yahoo has apparently had enough of Bing powering its searches. An unnamed source tells The Wall Street Journal that Yahoo has been “quietly trying to find a way out of its struggling Web-search partnership with Microsoft… but has so far failed in that effort.” The Journal’s source says that Yahoo CEO Marissa Mayer, a former Google executive, has been trying to free the company from the search deal ever since she took over last year but that Microsoft has been unwilling to cooperate. Mayer wants to scrap Yahoo’s Bing deal because “Yahoo’s revenue per search has been worse under the Microsoft deal than when it operated its own Web-search technology and advertising system,” the Journal writes.