Hi OP, I've thought about posting when I've seen your thread but was worried I was projecting. But here goes anyway...
I'm married and DH offered little support and went off on a fun weekend just after i miscarried leaving me looking after a toddler and feeling like a wreck. I really needed him. (He didn't end the relationship or anything, I'm sorry that happened to you, that's shit.)
He came back and said all the right things, he really was sorry etc. He didnt understand my feelings, he didn't know how to help. I wasnt communicating with him. He didn't have a great time away. All true. But do you know, I think he knew it was wrong to go but simply didn't want to miss the fun weekend that had been planned to be at home trying to cope with misery.
Our relationship was struggling a bit and when I miscarried I think I felt, oh, something big and real has happened, this will pull us together as he must feel sad for me.
I don't know how much is relevant but i suspect a fair bit is. I feel your partner has let you down badly.
I also think you might have more difficult feelings to come - not all of them necessarily rational. I know personally that miscarriage can intensify the desire to be pregnant again. Some posters on the miscarriage board talk about struggling with due dates etc. Will your relationship cope? Or would you have to pretend you arent feeling those things?
Sorry for long post. I hope you are looking after yourself and I'm sorry for your loss.