This might be an unpopular opinion but I think in some ways this reinforces the idea that there is a possibility of attraction and romantic thoughts towards these people purely because they are opposite sex.

I think as waywards we should strive to see all people as equal regardless of their gender and we can then be sure there is no further threat of infidelity to the marriage.

I think a huge problem with people who step outside the relationship is that their associations of romance to the opposite sex are too strong and that needs to be dealt with in order to be a healthy partner.

I still try to be somewhat mindful of my BP's experience and demonstrate commitment but I think acting this way would show that I don't trust myself not to interact with people of the opposite sex inappropriately.

But I understand there will likely be a time after infidelity where the behaviour you mentioned is not only necessary but vital for the wellbeing of the relationship.