Ahsoka had known for months. Honestly, it hadn't been that hard to figure out. The first thing she noticed was that her master never slept in the Temple when they were on Coruscant. Then, there had been the Blue Shadow Virus incident on Naboo, during which Anakin had practically lost his mind with worry over Ahsoka and the Senator. Basically, any time their missions involved Senator Amidala, Anakin could be counted on to freak out, in one way or another. However, concrete proof had not come until just four months before Ahsoka left the Order. They'd been escorting the Senator back to Coruscant after a particularly fraught diplomatic mission to Taris. Ahsoka, unable to sleep, had been walking to the canteen, hoping to find an off duty trooper to talk to, when Senator Amidala's door hissed open, and her master's left boot appeared in the corridor. Ahsoka immediately flung herself around the corner, and listened.
"I'm just glad you're safe" said Anakin softly, looking over his shoulder at the diminutive senator. She gave him a sweet smile, the one, now that Ahsoka thought of it, she reserved only for Anakin. Amidala stretched up on her toes and pressed her mouth to Anakin's.
"I'm fine, darling." She said. "You should get back to your quarters. This is hardly my apartment on Coruscant."
"I know." He said, and Ahsoka definitely heard a tinge of disappointment. "As soon as we drop you off, Ahsoka and I are headed to the Outer Rim again. I'll be gone for at least four months this time, maybe longer. I'll miss you, my love."
Ahsoka choked back her gasp and fled back to her bunk, mind racing. She had suspected that Anakin cared for the Senator as more than a friend, yes, but to think they were in a secret relationship? It was insane. Well, that certainly explained his sympathy to her feelings for Lux. As she listened to her master's boots in the corridor, Ahsoka couldn't help but worry for him. If the council, no, if anyone ever found out about what she had just seen, Anakin's career would be over. She resolved to keep it to herself. Ahsoka would not be the reason her master lost everything.
20 BBY, the Jedi Temple
"I understand. More than anything, I understand wanting to walk away from the Order." Anakin's voice was resigned. Ahsoka kept her face turned away. If she looked at him now, she knew she would stay.
"I know." She said, and then the enormity of his words hit her. He wasn't merely supporting her, he was talking about Senator Amidala! She couldn't let him face this alone. She whirled around. "Master, I know. I know about you and the Senator." Anakin's eyes widened, and his face went white beneath his tan.
"No, listen. I've known for months now. I'm not gonna turn you in or anything. What I'm saying is, you shouldn't have to deal with this secret alone. Promise me, Master. Promise me you'll talk to Obi-Wan about this. He'll understand, trust me."
"Ahsoka, I can't. It's too risky." Ahsoka reached out and grabbed his arm.
"No. Please. As-as a last gift to me. I'd feel so much better knowing you had someone to talk to. Just-please. I have a terrible feeling that something bad will happen if you don't tell him. Please, trust me."
"I do trust you. I-I'll tell him." Ahsoka smiled, relieved.
"Thank you, Master. I hope we'll meet again."
"The Force will be with you always, Ahsoka." She smiled again, squeezed his arm once more, and the turned to the Temple stairs.