Buffalo Bills defensive Mario Williams, Erin Marzouki, in happier days. (Image credit: David Duprey/AP)

By ABC News' Gina Sunseri:

Buffalo Bills defensive end Mario Williams has gone on the offensive. He wants the 10-carat $785,000 diamond engagement ring he gave to Erin Marzouki, his former fiancée , back.

Williams met Marzouki in Houston when he played for the Houston Texans football team. They got engaged on Feb. 12, 2011, when he presented her with the stunning 10-carat rock, according to a lawsuit filed in Harris County Court in Houston.

But their engagement didn't even last a year. Marzouki broke up with Williams last January, and he now wants the 10-carat diamond back.

The lawsuit details just how much Williams spent on Marzouki during their relationship. Items included an American Express credit card she could use to pay her living expenses - she rang up $108,000 in charges in one year - on top of the $230,000 in other gifts he showered on her that same year, according to the court record.

The lawsuit does smack of bitterness. Williams claims Marzouki used him for his fame - and fortune, according to court documents. Do the math: In one year he claimed he spent $1,123,000 on a fiancée who broke up with him just months after they'd become engaged.

"On or about Jan. 21, 2013, defendant (Marzouki) unilaterally terminated the parties engagement. The termination of the relationship was caused solely by the defendant. Defendant never intended to marry plaintiff (Williams) and used the relationship as a means to get to plaintiff's money and acquire gifts. Defendant has absconded with the diamond engagement ring," the lawsuit alleges.

What's the honorable thing for Marzouki to do? Give the ring back?

Williams' new contact with the Buffalo Bills was one of the most lucrative for a defensive player in NFL history. The contract is for six years, and is worth up to $100 million, with $50 million guaranteed.

No matter. Williams still wants that $785,000 ring back.