Realization
Mabel was working at a bar when he met her. She was very kind and sweet. He would always go to the bar whenever he was being overwhelmed with the thought of marrying Chloe, whom he only considered as a biological sister, even though he knew it wasn't so.
One time that he had a fight with his parents because of the same issue, he left the house and went to the bar and drank more than he should.
When he woke up, he found himself together with Mabel. She was weeping, claiming he raped her. Wilfred couldn't deny it because there were stains on the bed.
That was where he believed that Mabel was a virgin. He paid her a huge sum of money to forget about what happened and she agreed.
After that day, Wilfred stopped going to the bar and began to force himself to cultivate other feelings for Chloe. That was when he slept with her, thinking he would feel something other than a brotherly love for her, still, he failed.