Pregnant Man Thomas Beatie -- Divorce FINALIZED ... After Wife Gets Last Tooth

Thomas Beatie, aka "Pregnant Man," just finalized his nasty divorce from ex-wife Nancy but only after he agreed to hand over his beloved shark tooth collection.

The couple's divorce had dragged on for years and it was ugly ... they originally separated in 2012 and there's footage of Nancy attacking Thomas, throwing their computer in the pool, and at one point, he claimed she threatened to kidnap their kids forcing him to install a GPS tracker on her car.

In the end, they split most things evenly ... down to the custody of their 3 kids and even decided to forgo spousal and child support checks. But, Nancy was still able to sink one last bite ... demanding that she keep Thomas' prized shark tooth collection.

Thomas tells us he began collecting the teeth in 2006 on the North Carolina shore where he sprinkled the ashes of a deceased girlfriend. He'd collected 72 teeth ... even one from a megalodon.

He says he waved the white flag so the divorce could be over, and now plans on marrying his girlfriend Amber.