If there was any most emotional wedding they attended in the past few months, it would be Matthew and Olivia's wedding. In fact, it was a wedding that for a couple of months, they thought they wouldn't be able to attend because it was never going to happen. Matthew had already lost Olivia even after years of being together because of a moment's stupidity and ignorance. He let an outsider...someone Olivia was clear that she doesn't trust get in his head and ruined their relationship.
They all thought that it was impossible for Matthew to get Olivia back. She was gone for months without a trace. During those months, Matthew was in his worst and darkest moments. He lost Olivia therefore he also lost himself. There were even times when they all thought that Matthew would kill himself. He had stopped living.
