I have No sympathy for anyone who cheats, whatever the reason, whatever their sexual persuasion.
The only reason the OP wants to keep her dirty little secret is to avoid showing her husband what she really is, this talk of hurting the children etc. is rubbish, if she had considered them, or him, for one second, she would never have cheated. I don't differentiate between different flavours of infidelity, they are all equally ugly and selfish.
How is having sex with someone else an easier option than sitting down with your partner and saying " I'm unhappy , can we try and sort things out?".
She was testing the waters, what if she had fallen for the old friend? - I doubt she would have been so considerate of her husband's feeling then.
She will forever look at him and think " you poor deluded fool, look what I've got away with" - if she doesn't think it will affect her life from here on in, she's a fool too.
She must feel that she's cleansed herself by admitting things on here and even been validated by the others who would so easily lie to their partners.
By not telling, this will never go away.
Only she knows/suspects how he would react, she hasn't even had the decency to give us this vital piece of information.
I honestly wonder why she bothered posting in the first place, her mind was already made up - or has it just been the technological equivalent of the confessional box?