Let's recap the events quickly: Lady Geneva, having found out Jamie's real identity, threatens to out him as a former Jacobite rebel to the rest of the family, thereby ensuring that he'd be sent away to a less pleasant form of captivity. The price for her silence is that he come to her room, so she can try out sex with someone other than her soon-to-be husband, a man old enough to be her grandfather. Jamie, fearing the consequences her words might have on Jenny and the children back at Lallybroch, reluctantly agrees. That same night, he sneaks upstairs, and despite the circumstances, the two share a pretty sweet moment together.