Having not told for close to 3 years, I did not tell #1) because I didn’t want to hurt him. That part IS true. I couldn’t live with what I did, I didn’t want him to have that pain. But #2) because it would end my marriage and I couldn’t face that.
So yes, selfishness.
I hope you don't see this post as an attack on your character since I know that you now see how selfish your motives were back then, but your post perfectly illustrates in my mind why WS who claim they are remorseful and yet plan on taking it to their grave are only fooling themselves and I just wanted to use it as a jumping off point for my thoughts on the subject.
It's both sickening and sad to read posts from the WS who are still actively engaging in the cover up and their attempts to ease their own conscience with overstated(and sometimes nonexistent) altruistic motives. WS who refuse to confess almost universally claim that they don't want to hurt their BS and I believe some of them are sincere when they say that, but very few of them will acknowledge that the underlying motive for their lying is just self interest(keeping their marriage, image, job etc.) more so than any concern they may have for their BS well being.
My question to them is usually this "Why now are you so concerned and willing to be the martyr, where was this overwhelming concern for your BS while you were committing adultery?" I simply don't believe in their newly found moral compass since if they truly had changed to such a degree that their main focus is now their BS welfare, even if it comes at their expense, then being honest and transparent with their BS would be a given. You don't repeatedly lie to somebody you love more than yourself.
There can be genuine shame, guilt and sadness without confession, but there can be no repentance. Repentance means tuning around and going in the opposite direction of the path that you've been on, if you're still actively lying and deceiving your spouse then you have not repented at all. (Not you specifically LH.)
There are so many valid reasons for telling the truth, but each one of them pales in comparison to the simple fact that every person deserves to make their own life decisions with all of the cards on the table. Just think of all the different choices a BS might have made in their life if they only knew that their spouse had cheated on them. How many BS would never have moved to that new town, or taken that particular job, or given up that particular friendship if they weren't being left in the dark about their own marriage. Each major life decision they made while under the false assumption that they had a marriage based on love and honesty was in actuality the WS robbing them of their own volition.
The truly reprehensible cases I've seen(other than paternity fraud) are when the WS guilts their oblivious BS into marital counseling. Imagine the hubris it takes for a cheater to sit there and double team their BS with the counselor, going over just about everything the BS has ever done wrong, every perceived slight against the WS all while knowing what they've done to them. I've seen multiple WS who claim to be remorseful for their affair and yet deny their BS the truth while making them jump through hoops to "win" them back while the BS is completely unaware that they're now competing with the AP's "ghost".