How he feels and copes is entirely his business, until he seeks sympathy, comfort or a conversation.
This is about how he behaves towards OP. We know nothing of his feelings or his motivation.
Maybe he is upset, maybe he isn't. Imposing his upset on her by behaving shittily towards her, would not excuse his behaving shittily towards her. He is choosing to behave shittily towards a woman who is experiencing a miscarriage. We don't know why. At this point it doesn't matter why.
We do know what effect it is having on her. We do know it is inexcusibly nasty behaviour. We also know that he hasn't apologised, or sought to make any excuses - however much posters here might wish to offer them for him.
OP, I really think you need to distance yourself from him, until he comes to you with an apology and makes a sincere effort to win you back. Perhaps at that point he'll outline his feelings by way of an explanation - while recognising that they don't excuse his behaviour.
And didofino yes, how people feel about a pregnancy is the important thing. Wanted and unwanted pregnancies are different experiences. The issue here isn't what he thinks, or even what he feels. It is what he chose to say out loud to her, in what tone and with what accompanying behaviour.