Pardon me I seem to be a troublemaker. The Original Post sounded rather hypothetical. I am not sure if the Original Poster was seeking advice. I do not intend to give advice, but I am curious about Catholic beliefs and attitudes related to sex and marriage.
Things are pretty simple when adultery is defined as sexual relations with a married person other than your spouse. If you define it any other way, I think you run into contradictions or logical inconsistencies, unless perhaps you are very precise with your words.
That’s what I meant to illustrate by pointing out that a husband may cuddle his children. He may also be affectionate with them and have “lovey feelings” about them. Therefore cuddling, affection, and lovey feelings are not essential elements of adultery. One might even have some of those behaviors and feelings with a brother or sister, or a close friend, or someone with whom one has shared a powerful experience (like surviving a disaster).
So, if cuddling, affection, and lovey feelings are not key to adultery, what is? What is the essential element that I’ve failed to recognize, if it is not sex?
By the way, I do not disagree with arguments along the lines of “near occasion of sin,” or committing adultery in one’s heart (Mt 5:27-28), but once again I think the sin relates to sex. If not sex, then what exactly is it?