Since you hate your husband and obviously have no intention of adhereing to your wedding vows and have had someone else in your life for so long a time you'd be doing both your husband and your children a kindness by swallowing your distaste for divorce and initiating one. It couldn't be any uglier than the lie you're currently living.
Children are very sensitive, perceptive and instinctual.
Most of all, they learn what they live. They, at least, deserve better. You're the adult. It's up to you to give it to them. If this is a bit too blunt for you, remember, you did ask what I made of this.