Give it some more time and definitely consider therapy to work through your trauma and PPD. It may not change your mind but I think 7 mo PP is still pretty early to be completely ruling it out. But after time and therapy if you still don't want more then he needs to be OK with that. Could consider couples therapy as well if necessary.
Is your partner understanding of the struggle you’ve been through and how this has made you feel? I went through a difficult birth experience with my first and this really put me off having a second when the plan was always to have two before this. My partner was also pretty traumatised by my birth so was happy to just wait and hold off on those conversations though I knew he still wanted a second. After my son turned two I suddenly felt a lot better about the idea of having a second and I’m currently pregnant with our second. I certainly would not have felt able to even think about it when my son was only 7 months and I really needed the time to process everything and feel ready. However it is also totally valid if you never feel ready to have another. As you are the one who would be pregnant and give birth this decision is up to you and you would both have to be in agreement to have another. But for now I think the best thing would be to just hold off on thinking about it.
I was always iffy on kids, but I was willing to only for my husband (who wanted two.) I hated being pregnant and swore I'd never do it again. I kept asking him to get a vasectomy and he kept saying "Let's wait til he's a year old and see how we feel then." I had the most traumatic birth and am still having a horrific recovery. My husband quickly said he'd never put me through that again and started making the appointments a few months PP. He got snipped a month ago when I was 7 months PP. It's actually such a huge weight off to just make the decision. (My husband is 1 of 7 and all his siblings are having several kids. Our motto is "We're going for quality, not quantity" 😂)
I had a pre term birth and a 3 week NICU stay and had/have birth trauma as well. I had nightmares I was pregnant again, I said there is no way I’m getting pregnant ever again. In my experience things got so much better once she was 12 months. Something changed, I started feeling more like myself and when I think about her birth it doesn’t feel as sad as before. Sometimes I wonder if I should give her a sibling, but I quickly change my mind and say I’m one and done lol I told everyone, including my husband, that I didn’t want to talk about having a second baby.. we were just wasting our time and making me anxious because even if I wanted another baby it would be too soon. I told my husband let’s talk about this when she’s 24 months. We agreed that our priority is our daughter now, we have so much to learn as new parents