It's taken him a long time to tell Magnus this -- he knows it's taken a long time. But despite knowing that Magnus won't think he's done something wrong, he feels -- uncertain? Guilty? They've talked about how frightening it is to love someone mortal and ordinary, and now Galahad is both those things instead of just one. He feels as though he's made something harder for Magnus that wasn't before.

He sighs, I lost my power.