I say with all honesty I am in awe of the intelligence of the people on this forum and the comments they make. I know I am out of my league when discussions such as these come up. All I have to work with is my C average schooling to work with. With that in mind I'm confused here. This forum is filled with posts about being honest and telling your SO. To lie and keep things secret is wrong. Advice I take very seriously.

So please explain why a scenario such as this does not violate the prime directive of not lying to your SO.
I purposely put in the word scenario because I am not necessarily talking about this one incident.