Ask your spouse not to work late without informing you first. If this is an emergency, your spouse should call you and ask for your blessing and that of the two of you. Therefore, if your husband had an affair with a coworker, it's best to try to win it back by making yourself attractive once again. Aside from that, express your love and show him your affection.
Perhaps one of the main reasons why your husband does this is because he no longer feels loved by you because you no longer show and express your love for him as you used to be. The day before my husband cheated on me, he told me that he had a meeting with a client after work, now my husband normally has meetings with clients during work hours, not after work.