On the way to Burien the day before, Gideon explained to Desmond the expectations of a duke's wedding night. Even if they didn't sleep with one another, they needed to at least pretend. The legitimacy of their marriage would be doubted if they didn't seal their union with the physical aspect.
Leonor's responses to him throughout the day made Desmond certain he would never pursue that side of things with her. She didn't love him. She loved who he was when he was younger.
Change was inevitable but it seemed she was almost the same.
However, scars weren't the only way he had changed. His mind wasn't the same either. The once positive teenager he had been was chased away by monsters the first time he was stabbed on the battlefield.
At one point in his life, he was overflowing with desire for her. He had late nights thinking of only Leonor.