Still a Loving Family, Though
What would you do if you caught your spouse cheating? If you have any shred of self-respect left, you’d kick them out of the home and file for divorce the next day. We know, we know. You love your husband/wife and can’t live without them, etc., etc., but they cheated. There’s no coming back from that.
That’s just our two cents, anyway. The OP’s mother is a lot more forgiving than we could ever be. After finding out her husband was having his cake and eating it, too, she kicked him out of the home, only to have him move back later on.