NO-NOOKY NIGHTMARE FOR J.LO & BATMAN!

How Bennifer went from sizzle to fizzle

LAME lovebirds Jennifer Lopez and Ben Affleck's bickering took a big bite out of their bedroom antics - with sources telling The National ENQUIRER the action went from red-hot to no-go before the burned-out Batman hunk bolted! "J.Lo privately complains Ben wasn't up to par in the bedroom, that he stopped making an effort and became lazy and boring as a lover," tattles a tipster.

The Oscar winner, 51, decamped from their shared home last month for a pricey Brentwood rental less than two years after tying the knot with the demanding diva, 54.

Sources say the dance diva is also dealing with the pressures of her failing album and concert tour - and shocking news her scheduled Las Vegas residency may be in jeopardy due to lack of interest.