Does the husband's statement: "If you ever betray me, then everything we live together is forbidden (haram)" count as a divorce, and is it obligatory for me to confess to him about the betrayal?

We congratulate you on your repentance and advise you to increase your acts of obedience and to beware of anything that might lead you to fall into immorality. You must conceal yourself and not tell anyone what happened. Your husband's statement, "If you ever betray me, then everything we live is haram," conditions the prohibition on future betrayal and does not include what happened in the past. Beware of falling into immorality in the future, as this could result in you being prohibited to your husband, in addition to the sin. The most authoritative view regarding the prohibition of a wife is that it depends on the husband's intention.