My(28) husband(28) wants to separate. I'm 6 weeks away from giving birth.

My husband (28) just told me(28) that he wants to separate. We have a two year old, and I'm 6 weeks away from giving birth to our second.
He says he's been struggling for several months with this but did not mention this once to me. He doesn't think we're compatible in the long run. We haven't even been fully married a year. He thinks we have different views of family that can't be fixed.
I'm trying not to be hurt but I'm completely devastated.
Im feeling really ****ed up and just really need some support I guess. Like where do I even go from here. How come I'm not important enough to try for. Why was I so blind sided. How can I do this without hating him or myself? How can I tell if he's just having a break down, or if this is really it.
He mentioned that there's so much he wants to do in life, but apparently that doesn't involve me. He says we're still family but I don't feel that way. I feel betrayed. We were supposed to be best friends. Best friends wouldn't do this to each other.
I feel stupid. Like I should have known, like we rushed our relationship. We've been together 4 years, I've been pregnant and hormonal for most of it.
How am I going to take care of a newborn by myself?
I feel so unloved and heartbroken. I've been having stomach pains since last night. I'm worried about what this will do to the baby.
Tl:dr: husband wants to separate. He feels like it's an inevitability, so why draw it out.
EDIT: Thank you for all the replies, I've read them all and I will be following through.
For those pointing out that we haven't been married or in a relationship long, we've been close friends since we were 19. I thought I knew him. I don't regret anything, I love my children and until recently (see two months) our lives were fine. The only thing we ever fought about consistently was his mother.
We have been to counselling once in regards to how his mother was affecting our relationship, not even two weeks ago.
My hormonal outbursts? I cried once because we were out of KD.
Was our relationship perfect? No. They never are, but I've always maintained that I would try every avenue possible to make things work before giving up.
I'm most upset that he didn't give me or our family that same chance.
UPDATE:
He has confirmed via text that it is in fact more important to him that our children know his mother than us being together. He has said he is ready to move on.
That's all there is to it I guess.


Source.