Apparently, the issue is that the wedding went later than Lenny realized it would, since Adriana took a long time getting ready for the ceremony. "I understand they took longer than everyone thought, but you can't leave your wife here," Lisa says about Lenny. "You're part of the wedding party."
Finally, Lisa decides to go outside to chase Lenny down just before he gets into a limo. "Lenny, you can't leave me," she tells him. "Do you know what, this is very rude, okay?"
"I'm like a widow — I'm always alone," Lisa adds dramtically. "Just stay with your wife."
So does he decide to stay? You'll have to watch the clip to find out! And here we thought weddings were supposed to be joyous occasions.