Back then, Connor had tried many times to prove himself better than Oric, but Willow ignored all of his advances. As a teen, there was not much he could do, but Connor often tried to impress her with the latest and newest, and while Willow was always excited, and treated him as awe inspiring, she was never swayed to his side.
Desperate, Connor had even gone as far as to tell Willow that Oric was sleeping with another female friend of theirs. It was not true, but he had hoped to put a wedge between the pair by making Willow jealous. He did not expect her to respond by offering herself to Oric, in what he could only guess was a rushed decision to make him hers completely.