The only reason why Horner is still there is because the Thai owners have his back in what seems to be an internal power struggle that's getting out of hand. Whether those texts are real or not, that alleged affair with a subordinate alone would normally be more than enough to get rid of him. Even if consensual, there are always ethical and legal questions about misuse of power and influence. However, the Thai owners surely wouldn't care, given their own history...
Also, Jos is annoying as fuck though, because he's only playing political games. Someone who has battered women in the past is hardly the right person to be calling someone else out for extramarital affairs and abuse of power.