"Master Yoda charged me with tracking you down; and if I couldn't talk you out of whatever insanity you'd fallen into I would have to use lethal force. I figured Padme would know where you'd gone, so I paid her a visit. She couldn't believe me, but I knew she'd find you all the same, if only to ask for herself. I waited after I left, and then snuck onto her ship and stowed away.

"We ended up on Mustafar; she confronted you, and it was going well until you saw me step off the ship. You accused her of betraying you and tried to kill her. I managed to distract you and we fought.

"After our duel, I took Padme to a medic." His face is filled with sorrow as he regards Anakin. "The medics couldn't explain her rapid deterioration, save that she'd given up the will to live. She passed away shortly thereafter, and the children along with her."

He doesn't care what timeline Anakin is from, he won't betray the children's secret. So don't mind him if he indulges in a little bit of omission.

And he'll let Anakin read between the lines on how that duel ended.