I can empathize with you. You are right in your feeling of revulsion and sorrow over what you had to go through as your mother was committing adultery.

You have every right in confronting your mom about it and express your feelings towards her for her heinous acts. You may do so if you are prepared to face the consequences: she may put you out of the house and chastise you, etc. If you are on your own, you can tolerate it.

You should do this, especially, if she is persisting in sin.

If, however, she has repented and changed, then you need not bring it up now.