In February 2012, just one month before signing a six-year, $100 million contract with the Buffalo Bills, NFL defensive end Mario Williams asked his girlfriend Erin Marzouki to marry him. He did so by giving her a stunning 10-carat diamond engagement ring worth almost $800,000. But when their relationship fell apart a short time later, the couple decided to call the wedding off. They also ran into a problem: They both wanted the engagement ring.

Marzouki kept it initially. But now, Williams is suing his former fiancée for $785,000. In his lawsuit, he alleges that Marzouki "never intended to marry plaintiff and used the relationship as a means to get to plaintiff's money and acquire gifts." He wants a judge to force Marzouki to give him the ring back.

These court cases can be tricky, so we're not sure who will win out. But let this be a lesson to everyone out there: It's best to think long and hard about who you ask to marry you before you do it. Even if you don't go through with a wedding, it could end up costing you.

RELATED: The Most Expensive Divorces in Sports History

[via Pro Football Talk]