You ask such a great question, and I’m impressed that you made the possible connection between the attraction to your husband’s colleague and your anger. The fact that you’ve identified this as a likelihood means that it is worthy of us exploring it as an explanation.
If your attraction is a type of revenge because you are angry, then it may be a type of passive aggression. Passive aggression comes from an abundance of angry feelings and a desire to avoid direct conflict. When the clash would be too uncomfortable, ill-advised, or not feasible, a passive-aggressive response is likely. At its core, passive aggression grows out of ambivalence of wanting to be angry but not having either the ability or willingness to do it directly. In your instance, you got the man of your dreams, but his deception and lack of faithfulness put you into a puzzle.
The solution? Harboring an attraction to his colleague.
As you will learn in the link above, passive aggression can emerge in different forms. Your silent fantasy feelings about his junior colleague would be the silent version of potential destruction. It would be the counterbalance to his infidelity and could have the potential to hurt him in the way he hurt you. Also, it is cloaked in socially acceptable and formal environments, so even if your husband were to confront you-you would be “innocent” enough because your behavior wasn’t inappropriate.
As the article will point out other forms of passive-aggressive behavior in addition to the silent, obstructive, or withholding behaviors are
1. Sullen, insulting, or negative communication
2. Regularly deny, forget, or procrastinate
3. Noncommittal in their agreements
4. Doing things inadequately/with little care
5. Struggle between independence and dependency
One possibility is that you struggle with expressing their independence in a socially-acceptable way. Like many people who are passive-aggressive, there is a core frustration in their attempt to exert some control over their life. More often than not, they are often unassertive and don’t know how to be more decisive and sure of themselves. Typically they have difficulty expressing themselves assertively and positively.
As this is often the case, I would recommend reading the book Boundaries: When to Say Yes, How to Say No To Take Control of Your Life by Henry Cloud & John Townsend, or the book Assertiveness: How to Stand Up for Yourself and Still Win the Respect of Others by Judy Murphy. Either of these will be helpful in you speaking up more about your needs and issues with your husband.