Thanks everyone, I've gone to txt him soooo many times today and had to stop myself. Why am I worried about how he is feeling?
You're worried because he's your husband, with whom you have three young kids, and you love him. What he is putting you through is bewilderingly painful emotionally and, as you say, it actually seems unfathomable that he could do this to you. So you reject the apparent reality and stick to your normal comfort zone of loving your trustworthy husband. It's almost too terrifying not to.
I am so very sorry that this is happening to you. You do need to find your way to negotiate this unwanted and unfamiliar path, and there probably is more than just one option.
Kick him out, cut him off, hate him - properly fracture your possibly already broken life together - that's one way.
But how to do that when you live him? And your children love him? And you love your family unit?
I think your first step should not be draconian and dramatic. I think you should ask if he's come to counselling with you as it would help you.
And go from there. In that process, he should face what he's done, and that if he wants any chance of keeping you, he needs to make a serious commitment including cast-iron NC with her. And you will be able to say how you feel.
And you come out either stronger together, or apart. But you will have done your best. And been through a process that will help you either way.
That's my advice. No love does not go away just because someone hurts you. That's the prob.