From what I heard from a conversation with Malia, it was paul who cheated. He must have already been in a relationship in Russia when Paul first visited her. When Leora found out, she also tried to establish a relationship in Prague. However, she never gave up contact with Paul.
As for Georgia, I can't comment on that. I think that was just an issue when Leora tried to bring paul to Prague.
But it's been a long time since then and lo and behold everything is "almost" like before