Nothing they did was ever a secret. They'd know - the Fates knew, prophets knew, the fucking KGB and CIA probably knew - and he had never been subtle with his past advances.
He didn't want to hide anything from anyone. He wasn't that kind of person and she wasn't, either.
When he felt her lips on his cheek, he didn't pull away or try to push away. She seemed determined to go through with this even though Ares... had moved on.