Poppy, my heart goes out to you. What you are feeling is so normal. Loads of people will tell you, "It will get better", and it's true. But the truth is, whatever we say, you feel in such a dark place that you will have trouble believing us, just like you have trouble believing your friends when they tell you you are an attractive person with lots going for you. You think they're just saying it because they're your friends: but it is because you are an attractive person with lot's going for you that they are your friends ...
Have you seen a doctor? I think maybe you should. You sound as if you really are depressed, and there's no reason not to take any help that's going, whether that be medicine or counselling, to help you through this.
Beyond that, what can you do. Focus on yourself. Right now you don't feel lovable or attractive; your WH has, in effect, sent you that message in as aggressive a way as possible. The message he's sending you is: Look at me, I must be great cos I got OW. Look at OW, she must be great cos she's got me. As for you ... you got no-one.
Now I say: DON'T BUY INTO THAT. Of course he's going to tell himself (and you) that he is happy. Human beings do not tell the people they have left "I am miserable in my new relationship and feel a burden of terrible guilt for what I have done". Of course he's going to try to blame you and confirm his choice. It's human nature.
Don't put up with that. Keep contact with him to a minimum. You don't want to hear how happy he is. You don't need to tell him how miserable you are. You don't need to do anything right now except deal with the D, and get on with your life. Concentrate on what you have got: your friends, your child, your self-respect. Concentrate on what you can get from the divorce (appropriate parenting for your child, a fair financial settlement). Concentrate on those little things you can do, for yourself, for your child. And let him go his way. Maybe he will be very happy. You can be too. Maybe (more likely) this thing of his will end in tears. Doesn't matter to you. He's got to look after himself now; and you have got to look after yourself.
