No one here is saying that but cheating on your wife is very serious. It was most definitely not his first time doing it and as Corby said he probably would have kept on had he not been caught.Only the sinless can witness for Jesus? I think you're missing the basic premise of Christianity.
I truly wish the best for him and that he learns and moves on from this and that him and his wife can salvage their marriage but this whole event shows that he is not where he needs to be spiritually to be such a large and public representative for Christ.