I could have written your post in 2009. Same circs, 2 children, youngest 5mths. I had asked my gp to refer me for tubal ligation, but he refused, and they refused to sterilize me at dc2's section. The one time I felt ready after dc's birth & I fell pregnant.
I know that I couldn't do it again, medical reasons mainly. Already had 2 sections, pre eclmapsia, carpal tunnel, SPD. Still recovering from section/birth. I just couldn't do it.
Had the termination & felt instant relief, but also felt so alone. Why did dh get to live a "normal life" & I got to grieve. Yes, I did what was best, but you still need to grieve in a way. Why did he seem so dismissive of what I had been through? Why couldn't he understand how big a deal it was, yet also appreciate what I had done for the sake of all of us. A little understanding, some talking, some reassurance would have gone a long way, yet instead he said "it's all done now" hugged me quickly & moved on to what ever he was doing.
I internalised my grief, which turned into anxiety. A few months down the line I realised that I wasn't dealing as well I had thought I was (I didn't ever feel guilt, or regret it, my feelings mainly focused on "were my reasons good enough") and I sought counselling. It helped!
I also talked to a friend, that helped too. I came to realise that although I wanted this, I still had the right to grieve over the loss. And so I did.
DH told me recently that he really didn't see it was a big deal, because I wanted to do it! I told him how it affected me & he said he had no idea. I never even told him about the counselling at the time. Don't know why. I guess it all points to the fact that I felt like I had no support from him. He can't really explain it, he just said it didn't feel like a big deal to him. We had a problem, I sorted it. He thought that was it. I guess in some way I should have told him how I felt.
We didn't talk about for it a long time, because I couldn't understand why it didn't affect dh as it did me.
In short, it is still very early days. Find someone you can confide in that isn't your dh (I'll be happy to listen) and seek some counselling. It really will help. Be kind to yourself. Of course you are entitled to feel sad, and your dh really needs to understand that! Please don't keep your feeling locked away, I don't think that will help at all.
You will come out of this, op. You really will. 4 years on, I don't look back. I looked after a friends little one a while ago & I had that little one & my youngest on my lap & I had a peep at what my life would have been like & I didn't like it. I am glad I took the path I did, I am not really cut out for more children. I have now been sterilized, so more proof that my baby raising days are done.