The event of the previous day caused Francis to feel guilty. He knew he shouldn't have done what he did. Dave was the only guy who could make Amelia happy but he destroyed it because of his own selfish reasons.
He knew he didn't deserve Amelia but he couldn't help but want her. He was starting to realize that maybe he had liked Amelia all those years. Maybe the reason he was always after her was because he wanted her attention. if he had known that things would turn out this way, he would have prevented it sooner.
but sadly it was too late to cry after the milk has...