Allen Iverson's Estranged Wife: He's Buying Diamonds ... And I Can't Pay Rent!

Allen Iverson's divorce has taken a nasty turn -- according to his estranged wife, the former NBA star went on a massive spending spree after she filed for divorce, leaving her completely penniless.

Tawanna just filed new docs in their bitter divorce battle -- claiming ever since she filed for divorce in June, Allen stopped depositing money in their joint bank account ... and then made several large cash withdrawals, including one for $20,000 ... which he spent on diamond jewelry.

Tawanna claims the account was $23,000 in the red at the time she filed the court docs -- and she's been unable to pay the bills ... or provide for their 5 kids.

According to Tawanna -- who says she gave up her career to be a stay-at-home mom -- Allen is worth over $20 million ... and refuses to help her out simply out of spite.