Ex-Girlfriend and Celebrating - joke

A husband is sitting with his wife at his 65th high school reunion. The husband kept staring at a drunken lady swigging a case of Miller Lite. The wife was getting jealous that her husband was staring at the lady instead of her. So she demanded “Do you know her!?!”. “Yes” said the husband calmly. “She’s an ex-girlfriend of mine. We split up when we was in 11th grade. And I heard she hasn’t been sober since.” he said. “My god!” said the wife. “Who would think that someone could go that long celebrating?”