Tony, a soldier returning from Iraq after a year of active duty, found out that his wife couldn't wait for some lovin' while he was gone by checking his Wii. When he confronted her with his friends' accusations, she claimed that she only kissed another man once. However, after checking his Mii channel for war buddies he discovered a Mii he didn't create.
When he went through the calendar, he found that his wife and the man had spent several nights together playing Wii bowling. Tony has since separated and filed for divorce.
You gotta feel for the poor guy. He spends all this time serving our country only to come home and see a cartoon character who looks "strikingly similar to [his] wife's [alleged lover]". I can only guess what the original phrase was, but I'm pretty sure it wasn't "Mario Party expert." [Gamepro]