NoCapes. you are doing so well.
If he thinks that ANYONE would be 'happy' while being left alone to recover from something as traumatic as the loss of your baby so late in pg, well, how can you trust his view on anything?
How you react is up to you. You are NOT over-reacting, and if you were , your feelings, your emotions, you are allowed to react how you feel. He is trying to make your feelings Unimportant, while his are the most important ones.
When push comes to shove, you don't have to justify how you feel or that you want to end the relationship. That you want to end it is enough. You don't have to prove any reasons to him.
How the HELL he could dismiss your feelings (telling you you were 'in a mood' after he stayed out all night) and then think he could leave you alone all day, staying in bed, ignoring his children, when you are recovering from the delivery of your lost baby and managing young kids and a baby, and think he can say 'I love you' remains a mystery. No one treats someone they love like that.
It is emotionally abusive to dismiss your feelings, try and blame you, and guilt trip you.
You deserve someone who actually loves you and treats you well, and you need to have the experience of that to know just how bad, selfish and unkind, his behaviour is.