Buffalo Bills football star Mario Williams, who signed the biggest contract in team history last year, has filed a lawsuit against his former fiancée in Houston, seeking the return of a 10-carat diamond engagement ring reportedly worth $785,000.

The lawsuit alleges that Erin Marzouki “unilaterally terminated” the engagement in January for reasons that were “caused solely” by her.

Furthermore, Williams alleges that Marzouki never intended to marry him and that she used their relationship as a means to “get … money and acquire gifts.”

“[Marzouki] has absconded with the diamond ring,” according to the suit. “[Williams] has demanded that Defendant return the diamond engagement ring, but Defendant has failed and refused to do so.”

The 28-year-old defensive end filed the lawsuit Friday in Harris County Court in Houston. The Buffalo News obtained a copy of the document Monday.

The lawsuit comes almost 14 months after Williams joined the Bills, signing a six-year, $100 million contract with $50 million in guaranteed money. When it was signed, the contract made Williams the highest-paid defensive player in National Football League history and by far the highest-paid in Bills history.

So far, nothing has been filed in the Houston court giving Marzouki’s side of the story. A News reporter left a telephone message for Marzouki in Houston but did not receive a return call. Court officials said they do not know who represents Marzouki in the case.

Williams’ Houston attorneys, Monica S. Orlando and Michael G. Orlando, could not be reached Monday afternoon to comment.

The football star contends in court papers that Marzouki agreed to marry him but also agreed that, if the wedding was ever called off, she would return the ring that Williams bought for her.