"That was for Thane, you son of a bitch," she hisses as her blade pierces Kai Leng's chest, and Kaidan dies a little, too.

He looks at his Commander and sees such pain and anger in her eyes as he'd never seen before, not even when they were leaving Earth. He knew she had an affair with the drell. What he did not know was what he understands now with too perfect a clarity.

This lasts for a split second, and then Shepard is her composed, professional self again. Kaidan thinks not even she noticed anything change in her behaviour. He chooses to say nothing.

He will have to deal with the fact Shepard loves a dead assassin after they have won the goddamn war.