Whenever you cross the agreed rules and boundaries, it's cheating in an open marriage. However, it's not always intentional. Perhaps, your contract says you can’t hug… however, you hug them while engaging in a sexual position. You did that unintentionally without your spouse’s consent. Keep your promises wisely… if you can’t keep a promise, don’t hide it. Confess to your spouse and negotiate the rules. If your spouse denies negotiation, figure out some other solution.