Trouble is we only have Jim's side, there is always two sides to every story. So they really should have both agreed to address any rumours or both say nothing. Also if Tan comes out now and says Jim didn't cheat they it just looks like Jim told her to say it. The trouble Jim has is that some people are going to believe he cheated no matter what he says and he really needs to get over that! Him, Tan and Sarah know the truth so that should be enough.